fix: Image utils optional dependency errors and unblock unit tests on minimal env

[Shizoqua]

Summary

This PR fixes behavior in feast.image_utils when optional image dependencies are not installed, and adds unit tests to cover the expected failure mode.

While validating the fix locally, I also addressed a few test-harness issues that prevented running unit tests in a minimal environment (without integration/auth optional deps).

Changes

• Ensure validate_image_format and get_image_metadata call _check_image_dependencies() so they raise a clear ImportError when feast[image] deps are missing (instead of failing with a NameError due to missing PIL.Image).
• Add unit tests for missing optional image dependencies:
  • sdk/python/tests/unit/test_image_utils_optional_deps.py
• Unblock unit test execution in minimal environments:
  • Update pytest.ini for pytest 8 compatibility (remove invalid warning filter) and remove env= config that requires extra plugins.
  • Make tests/conftest.py safe to import without optional integration/auth dependencies (guard imports).
  • Fix Windows multiprocessing start method selection (sys.platform is win32, not windows).

Why

• Prevent confusing runtime failures when optional feast[image] dependencies are not installed.
• Improve contributor experience by allowing unit tests to run without requiring integration-only packages.

Test Plan

• python -m pytest -q tests/unit/test_image_utils_optional_deps.py

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[Copilot]

Pull request overview

This PR fixes error handling in feast.image_utils when optional image dependencies are missing and enables unit tests to run in minimal environments without integration dependencies.

• Adds _check_image_dependencies() calls to validate_image_format and get_image_metadata to raise clear ImportError when image dependencies are missing
• Adds unit tests to verify optional dependency handling
• Updates test infrastructure to support running unit tests without optional integration/auth dependencies

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
sdk/python/feast/image_utils.py	Added dependency checks to image validation and metadata extraction functions
sdk/python/tests/unit/test_image_utils_optional_deps.py	New unit tests verifying ImportError behavior when image dependencies are unavailable
sdk/python/tests/conftest.py	Wrapped integration and auth test imports in try-except blocks to allow conftest loading without optional dependencies; fixed Windows platform detection
sdk/python/pytest.ini	Removed deprecated pytest configuration for pytest 8 compatibility

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[Shizoqua]

Good day @franciscojavierarceo
I would appreciate it if my PR is looked at and reviewed.

[Shizoqua]

Good day @franciscojavierarceo
I would appreciate it if my PR is reviewed.

[Shizoqua]

Hello,
Good day @franciscojavierarceo
Just a quick reminder of my PR getting reviewed.

[devin-ai-integration]

Devin Review found 1 potential issue.

View issue and 6 additional flags in Devin Review.

[Shizoqua]

Hello,
Good day @franciscojavierarceo
Just a quick reminder of checking out my PR.