fix(oidc settings): effective JWS algorithm setting

[darnaut]

Due to a bug in OidcConfigs, the preferredJwsAlgorithm setting was never used when OIDC "dynamic" settings are set/enabled. Probably to workaround this bug, a change was made to use auth.oidc.preferredJwsAlgorithm from the application configuration (same as AUTH_OIDC_PREFERRED_JWS_ALGORITHM environment variable) if the preferredJwsAlgorithm setting was not specified in the OIDC dynamic settings - which is always the case due to the bug. This workaround also prevents us from simply using an existing preferredJwsAlgorithm setting as it could differ from an actually used configuration option which might have a different value - causing breakage to existing deployments.

This change introduces a new preferredJwsAlgorithm2 field in the OIDC settings that is actually used if set. The workaround is also partially preserved in that if preferredJwsAlgorithm2 is not set, the value from auth.oidc.preferredJwsAlgorithm is used. The response from the auth/getSsoSettings endpoint now returns the value of preferredJwsAlgorithm2 but still uses the same field name.

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