fix(oauth2): correctly return an error on client_credentials and jwt_profile (#8092)

# Which Problems Are Solved

When an error occurred during the oidc session creation from
client_credentials or jwt_profile, the error was ignored.

# How the Problems Are Solved

Return the error.

# Additional Changes

None.

# Additional Context

- relates to #7822 
- noticed internally
- backport to 2.53.x

internal/api/oidc/token_client_credentials.go

@@ -46,6 +46,9 @@ func (s *Server) ClientCredentialsExchange(ctx context.Context, r *op.ClientRequ
 		nil,
 		false,
 	)
+	if err != nil {
+		return nil, err
+	}
 
 	return response(s.accessTokenResponseFromSession(ctx, client, session, "", "", false, true, false, false))
 }