Remove Gutenberg Video block from excerpt to hide VideoPress URLs

[SiobhyB]

Fixes the iOS side of wordpress-mobile/gutenberg-mobile#6669

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Description:

Following the implementation of VideoPress v5, media uploaded to the video block on supported sites will automatically convert to VideoPress. This has led to VideoPress URLs being visible alongside excerpts in the post list section.

To remove all references to VideoPress from the post excerpt, this PR extends the strippingGutenbergVideoPress function to include video blocks.

See wordpress-mobile/WordPress-iOS#22713 for the main iOS companion to this PR.

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To Test:

1. In the app, select a WordPress.com site to edit and open the post editor.
2. Add the Video block and go through the steps to add a video.
3. Save your changes and return to the post list.
4. Verify the VideoPress URL does not display in the post list.

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Screenshots:

Before	After

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Regression Notes:

1. Potential unintended areas of impact

   • As we're making changes to the regex that filters out the VideoPress block from the excerpt, there is a chance this PR could unintentionally change the existing functionality.

2. What I did to test those areas of impact (or what existing automated tests I relied on)

   • I manually tested the changes and relied on the existing test that verifies VideoPress blocks remain correctly hidden.

3. What automated tests I added (or what prevented me from doing so)

   • I added a new test in d9d8d04 that verifies regular video blocks are removed from the post excerpt.

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• I have considered if this change warrants release notes and have added them to the appropriate section in the CHANGELOG.md if necessary.

[derekblank]

I was able to following the testing steps successfully and verified I did not observe the video URL in the Posts list. LGTM. 🚀