Austenem/CAT-1118 Check for missing symlinks

[austenem]

Summary

Adds checks before trying to access a workspace's symlinked files (resolves 2023 workspaces API bug that resulted in malformed workspaces with empty current_workspace_details objects).

Design Documentation/Original Tickets

CAT-1118 Jira ticket

Testing

Was able to reproduce the original error by calling isWorkspaceAtDatasetLimit on a workspace with a manually deleted current_workspace_details object, and used the same method to confirm that the issue was resolved by this fix.

Checklist

• Code follows the project's coding standards
  • Lint checks pass locally
  • New CHANGELOG-your-feature-name-here.md is present in the root directory, describing the change(s) in full sentences.
• Unit tests covering the new feature have been added
• All existing tests pass
• Any relevant documentation in JIRA/Confluence has been updated to reflect the new feature
• Any new functionalities have appropriate analytics functionalities added