trusted_cluster resource renames itself, breaking subsequent updates

[hugoShaka]

Expected behaviour:

• As a user I create a resource called clusterA while my remote cluster real name is clusterA.example.com
  Either I have a name mismatch error when I create the resource, or the resource name stays clusterA

Current behaviour:

• The resource is renamed from clusterA to clusterA.example.com in the backend
• I don't have a unique identifier to get the resource anymore
• If I edit the role mapping and apply again for clusterA it silently drop my changes

Bug details:

• Teleport version v16.4.2
• Recreation steps: create a TC resource whose name is different than the root cluster name
• Debug logs

Additional notes

• this is blocking TC support in the operator

[bernardjkim]

Hey @hugoShaka, I've written up a small patch to add resource name validation for trusted_clusters in #49169. However, is there any concern for potentially breaking automation for some users that have been using an invalid trusted_cluster name up until now?