resource/gitlab_project: Only execute custom `default_branch` logic for GitLab < 14.10

Timo Furrerrequested to merge
github/fork/timofurrer/feature/do-not-execute-default-branch-handling-for-new-releases into main

GitLab 14.10 released with a bugfix for the default_branch field in the Projects REST API so that our custom logic is no longer required.

see gitlab#333426

Once GitLab 15.1 is out I suggest to remove that code entirely.

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