Fix pytest 9 deprecation warnings

[rly]

Overview:

• Update pytest_ignore_collect hooks to use collection_path parameter instead of deprecated path parameter (py.path.local -> pathlib.Path)
• Remove pytest.mark decorators from fixtures (marks on fixtures have no effect in pytest 9+)

🤖 Generated with Claude Code

Addresses:

Type of Fix:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing
  functionality to not work as expected)
• Documentation Change

Solution:

Changes:

Validation:

Screenshots:

Unit Tests:

Script to reproduce error and fix:

Configuration details:

Tests are still failing due to other errors. These will be fixed in a separate PR.

Checklist

• My code follows
  Allen Institute Contribution Guidelines
• My code is unit tested and does not decrease test coverage
• I have performed a self review of my own code
• My code is well-documented, and the docstrings conform to
  Numpy Standards
• I have updated the documentation of the repository where
  appropriate
• The header on my commit includes the issue number
• My Pull Request has the latest AllenSDK release candidate branch
  rc/x.y.z as its merge target
• My code passes all AllenSDK tests

Notes: