Fix panic in aws.rds.Proxy

[t0yv0]

Fixes #3835 by reverting the upstream change until the upstream issue is root-caused and resolved. Passing an empty object to auths field of aws.rds.Proxy should no longer panic.

[github-actions]

Does the PR have any schema changes?

Looking good! No breaking changes found.
No new resources/functions.

Maintainer note: consult the runbook for dealing with any breaking changes.

[github-actions]

Is README.md missing any configuration options?

assumeRoleWithWebIdentity not found in Configuration section
customCaBundle not found in Configuration section
defaultTags not found in Configuration section
ec2MetadataServiceEndpoint not found in Configuration section
ec2MetadataServiceEndpointMode not found in Configuration section
httpProxy not found in Configuration section
httpsProxy not found in Configuration section
ignoreTags not found in Configuration section
noProxy not found in Configuration section
retryMode not found in Configuration section
s3UsEast1RegionalEndpoint not found in Configuration section
sharedConfigFiles not found in Configuration section
skipRequestingAccountId not found in Configuration section
stsRegion not found in Configuration section
tokenBucketRateLimiterCapacity not found in Configuration section
useDualstackEndpoint not found in Configuration section

Please add a description for each of these options to README.md. Details about them can be found in either the upstream docs or schema.json.

[t0yv0]

Test failures fixed on master; rebasing.

[t0yv0]

/release patch