Generate missing next-gen keeps loading in settings page without generating avif/webP when enable/disable avif with next-gen gallery

[Mai-Saad]

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• Made sure you’re on the latest version => 2.2.1
• Used the search feature to ensure that the bug hasn’t been reported before

Describe the bug avif /web not automatically generated when enable/disable avif while next-gen gallery is on and have some images

To Reproduce Steps to reproduce the behavior:

1. activate imagify
2. activate next-gen gallery plugin
3. add some images at the gallery => images optimized and webp created
4. in imagify settings -> enable avif
5. notice generating missing next-gen keeps loading with -n/0

Expected behavior A clear and concise description of what you expected to happen.

• automatically generate avif/webp when enable/disable avif
• generate missing next-gen count is 0/n and increment

Screenshots If applicable, add screenshots to help explain your problem.

Additional context Add any other context about the problem here.

• similar issue was there in media library only when deactivate avif https://github.com/wp-media/imagify-plugin/issues/838

Acceptance Criteria (for WP Media team use only) Clear instructions for developers, to be added before the grooming