Modify and quarantine branch_with_unusual_name_spec.rb

What does this MR do and why?

Describe in detail what your merge request does and why.

Modifies branch_with_unusual_name_spec.rb to check for console errors to avoid false positives. So far it only failed once (see #383863 (closed)) however the bug for a branch containing a # in its name can be reproduced consistently manually.

Also quarantines the test (that will start failing repeatedly after the modification) until the bug is fixed in #364565 (closed).

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