500 when deleting share role/permission

[ScharfViktor]

related #8842

Steps:

• share file with viewer role
• try to delete role (role= or permissions=) curl -k https://localhost:9200/ocs/v2.php/apps/files_sharing/api/v1/shares/a18240d0-420a-4c74-99ed-6c933cad6944:e6599e5f-8afa-4088-9236-98c8ee450a5a:02182da5-ea39-4bc0-9742-d018c7609dff -X PUT -d "expireDate=2026-04-28T23%3A59%3A59.999%2B01%3A00&role=" -vk -u admin:admin

Actual: 500 error
server log:
2024-03-27T12:53:25+01:00 ERR http end="27/Mar/2024:12:53:25 +0100" host=127.0.0.1 method=PUT pkg=rhttp proto=HTTP/1.1 service=frontend size=164 start="27/Mar/2024:12:53:25 +0100" status=500 time_ns=9802167 traceid=2b26d140507bd16005668c0b84ceed77 uri=/ocs/v2.php/apps/files_sharing/api/v1/shares/a18240d0-420a-4c74-99ed-6c933cad6944:e6599e5f-8afa-4088-9236-98c8ee450a5a:02182da5-ea39-4bc0-9742-d018c7609dff url=/v2.php/apps/files_sharing/api/v1/shares/a18240d0-420a-4c74-99ed-6c933cad6944:e6599e5f-8afa-4088-9236-98c8ee450a5a:02182da5-ea39-4bc0-9742-d018c7609dff

Expected: 400 error with message role must not be empty