cannot login when running ocis with keycloak

[individual-it]

Describe the bug

After #8051 got merged all integration tests for https://github.com/owncloud/ocis-php-sdk are failing because the server responds with 500
I can get a token, but using it returns e.g. Server error: GET https://ocis.owncloud.test/graph/v1.0/me/drives?%24orderby=name%20asc` resulted in a 500 Internal Server Error response`

@kobergj could you help to chec if we have a configuration issue in the setup or if is there a bug?

Steps to reproduce manually

1. add these hosts to /etc/hosts:

   127.0.0.1	ocis.owncloud.test
   127.0.0.1	keycloak.owncloud.test
   

2. get docker-compose file from: https://github.com/owncloud/ocis-php-sdk/blob/main/tests/integration/compose.yaml
3. get docker folder from: https://github.com/owncloud/ocis-php-sdk/tree/main/tests/integration/docker
4. run docker compose up
5. with the browser navigate to https://keycloak.owncloud.test/ and accept the certificate
6. with the browser navigate to https://ocis.owncloud.test/ and accept the certificate
7. try to login as admin

Expected behavior

login should work

Actual behavior

cannot login

Setup

see https://github.com/owncloud/ocis-php-sdk/blob/main/tests/integration/compose.yaml
and https://github.com/owncloud/ocis-php-sdk/blob/main/tests/integration/docker/keycloak/ocis-realm.dist.json

Additional context

Logs:

keycloak-ocis-1      | {"level":"debug","service":"storage-system","pkg":"rgrpc","traceid":"d5333330f020b72c4dfcf1a9594927ca","user-agent":"grpc-go/1.60.1","from":"tcp://127.0.0.1:33740","uri":"/cs3.storage.provider.v1beta1.ProviderAPI/ListContainer","start":"27/Dec/2023:04:19:19 +0000","end":"27/Dec/2023:04:19:19 +0000","time_ns":190825,"code":"OK","time":"2023-12-27T04:19:19Z","line":"github.com/cs3org/reva/v2@v2.18.0/internal/grpc/interceptors/log/log.go:69","message":"unary"}
keycloak-ocis-1      | {"level":"error","service":"graph","middleware":"requireAdmin","userid":"c478b5cd-2103-4ff0-94fc-71c0e5329fbc","time":"2023-12-27T04:19:19Z","line":"github.com/owncloud/ocis/v2/services/graph/pkg/middleware/requireadmin.go:39","message":"No roles assigned to user"}
keycloak-ocis-1      | {"level":"debug","service":"graph","request-id":"","proto":"HTTP/1.1","method":"POST","status":401,"path":"/graph/v1.0/users","duration":109.645082,"bytes":150,"time":"2023-12-27T04:19:19Z","line":"github.com/owncloud/ocis/v2/ocis-pkg/middleware/logger.go:27"}
keycloak-ocis-1      | {"level":"warn","service":"proxy","OData Error":"Unauthorized","time":"2023-12-27T04:19:19Z","line":"github.com/owncloud/ocis/v2/services/proxy/pkg/user/backend/cs3.go:256","message":"Error Response"}
keycloak-ocis-1      | {"level":"error","service":"proxy","error":"401 Unauthorized","time":"2023-12-27T04:19:19Z","line":"github.com/owncloud/ocis/v2/services/proxy/pkg/user/backend/cs3.go:198","message":"Error creating user"}
keycloak-ocis-1      | {"level":"error","service":"proxy","error":"401 Unauthorized","time":"2023-12-27T04:19:19Z","line":"github.com/owncloud/ocis/v2/services/proxy/pkg/middleware/account_resolver.go:113","message":"Autoprovisioning user failed"}
keycloak-ocis-1      | {"level":"info","service":"proxy","proto":"HTTP/1.1","request-id":"8da0dc50-dc4d-4bfe-9199-1955882229b0","traceid":"8867c684bea80316690f520bace988c1","remote-addr":"192.168.48.1","method":"GET","status":500,"path":"/ocs/v1.php/cloud/user","duration":207.601057,"bytes":0,"time":"2023-12-27T04:19:19Z","line":"github.com/owncloud/ocis/v2/services/proxy/pkg/middleware/accesslog.go:34","message":"access-log"}
keycloak-traefik-1   | {"ClientAddr":"192.168.48.1:48160","ClientHost":"192.168.48.1","ClientPort":"48160","ClientUsername":"-","DownstreamContentSize":0,"DownstreamStatus":500,"Duration":208093763,"OriginContentSize":0,"OriginDuration":208068820,"OriginStatus":500,"Overhead":24943,"RequestAddr":"ocis.owncloud.test","RequestContentSize":0,"RequestCount":265,"RequestHost":"ocis.owncloud.test","RequestMethod":"GET","RequestPath":"/ocs/v1.php/cloud/user","RequestPort":"-","RequestProtocol":"HTTP/2.0","RequestScheme":"https","RetryAttempts":0,"RouterName":"ocis@docker","ServiceAddr":"192.168.48.3:9200","ServiceName":"ocis@docker","ServiceURL":{"Scheme":"http","Opaque":"","User":null,"Host":"192.168.48.3:9200","Path":"","RawPath":"","OmitHost":false,"ForceQuery":false,"RawQuery":"","Fragment":"","RawFragment":""},"StartLocal":"2023-12-27T04:19:19.744045868Z","StartUTC":"2023-12-27T04:19:19.744045868Z","TLSCipher":"TLS_AES_128_GCM_SHA256","TLSVersion":"1.3","downstream_X-Request-Id":"8da0dc50-dc4d-4bfe-9199-1955882229b0","entryPointName":"https","level":"info","msg":"","origin_X-Request-Id":"8da0dc50-dc4d-4bfe-9199-1955882229b0","request_X-Request-Id":"8da0dc50-dc4d-4bfe-9199-1955882229b0","time":"2023-12-27T04:19:19Z"}
keycloak-traefik-1   | {"ClientAddr":"192.168.48.3:51184","ClientHost":"192.168.48.3","ClientPort":"51184","ClientUsername":"-","DownstreamContentSize":5970,"DownstreamStatus":200,"Duration":4113321,"OriginContentSize":5970,"OriginDuration":4088755,"OriginStatus":200,"Overhead":24566,"RequestAddr":"keycloak.owncloud.test","RequestContentSize":0,"RequestCount":270,"RequestHost":"keycloak.owncloud.test","RequestMethod":"GET","RequestPath":"/realms/oCIS/.well-known/openid-configuration","RequestPort":"-","RequestProtocol":"HTTP/1.1","RequestScheme":"https","RetryAttempts":0,"RouterName":"keycloak@docker","ServiceAddr":"192.168.48.5:8080","ServiceName":"keycloak@docker","ServiceURL":{"Scheme":"http","Opaque":"","User":null,"Host":"192.168.48.5:8080","Path":"","RawPath":"","OmitHost":false,"ForceQuery":false,"RawQuery":"","Fragment":"","RawFragment":""},"StartLocal":"2023-12-27T04:19:20.052192019Z","StartUTC":"2023-12-27T04:19:20.052192019Z","TLSCipher":"TLS_AES_128_GCM_SHA256","TLSVersion":"1.3","entryPointName":"https","level":"info","msg":"","time":"2023-12-27T04:19:20Z"}