fix: Remove duplicate test file

Remove tests/test_project_removal_bug.py as it's a duplicate of the
existing test_issue_254_foreign_key_constraints.py test.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>
Signed-off-by: Joe P <joe@basicmemory.com>

Author: jope-bm