fix: Exposes role_mapping_id for federated_settings_org_rolemapping

[EspenAlbert]

Description

Exposes role_mapping_id for federated_settings_org_rolemapping

Before this change, you had to Base64 decode the .id to find the role_mapping_id, this exposes the field directly

Link to any related issue(s): CLOUDP-248288

Type of change:

• [ ] Bug fix (non-breaking change which fixes an issue). Please, add the "bug" label to the PR.
• [ ] New feature (non-breaking change which adds functionality). Please, add the "enhancement" label to the PR. A migration guide must be created or updated if the new feature will go in a major version.
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected). Please, add the "breaking change" label to the PR. A migration guide must be created or updated.
• [ ] This change requires a documentation update
• [ ] Documentation fix/enhancement

Required Checklist:

• [x] I have signed the MongoDB CLA
• [x] I have read the contributing guides
• [x] I have checked that this change does not generate any credentials and that they are NOT accidentally logged anywhere.
• [x] I have added tests that prove my fix is effective or that my feature works per HashiCorp requirements
• [x] I have added any necessary documentation (if appropriate)
• [x] I have run make fmt and formatted my code
• [x] If changes include deprecations or removals, I defined an isolated PR with a relevant title as it will be used in the auto-generated changelog.
• [x] If changes include removal or addition of 3rd party GitHub actions, I updated our internal document. Reach out to the APIx Integration slack channel to get access to the internal document.

Further comments

acceptance test (updated)

[EspenAlbert]

@oarbusi if the user wants to import the resource in another configuration or modify it with another tool. The same way, we expose the id of almost any other resource. Right now, they can find the role_mapping_id, but they would need to Base64 decode the id and do string parsing to find the role_mapping_id 😅

[EspenAlbert]

No approval from the docs team, but merging this after waiting more than 24 hours 👍