Remove Gutenberg Video block from excerpt to hide VideoPress URLs

[SiobhyB]

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

Description

See wordpress-mobile/WordPress-iOS-Shared#352 for more information and testing steps.

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 wordpress-mobile/WordPress-iOS-Shared@d9d8d04 that verifies regular video blocks are removed from the post excerpt.

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PR submission checklist:

• I have completed the Regression Notes.
• I have considered adding unit tests for my changes.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

Testing checklist:

• WordPress.com sites and self-hosted Jetpack sites.
• Portrait and landscape orientations.
• Light and dark modes.
• Fonts: Larger, smaller and bold text.
• High contrast.
• VoiceOver.
• Languages with large words or with letters/accents not frequently used in English.
• Right-to-left languages. (Even if translation isn’t complete, formatting should still respect the right-to-left layout)
• iPhone and iPad.
• Multi-tasking: Split view and Slide over. (iPad)

[dangermattic]

	1 Warning
⚠️	This PR is assigned to the milestone 24.4. This milestone is due in less than 4 days. Please make sure to get it merged by then or assign it to a milestone with a later deadline.

Generated by 🚫 Danger

[wpmobilebot]

📲 You can test the changes from this Pull Request in WordPress Alpha by scanning the QR code below to install the corresponding build.

	App Name	WordPress Alpha
	Configuration	Release-Alpha
	Build Number	pr22713-58dbc15
	Version	24.3
	Bundle ID	org.wordpress.alpha
	Commit	58dbc15
	App Center Build	WPiOS - One-Offs #9046

Automatticians: You can use our internal self-serve MC tool to give yourself access to App Center if needed.

[wpmobilebot]

📲 You can test the changes from this Pull Request in Jetpack Alpha by scanning the QR code below to install the corresponding build.

	App Name	Jetpack Alpha
	Configuration	Release-Alpha
	Build Number	pr22713-58dbc15
	Version	24.3
	Bundle ID	com.jetpack.alpha
	Commit	58dbc15
	App Center Build	jetpack-installable-builds #8089

Automatticians: You can use our internal self-serve MC tool to give yourself access to App Center if needed.

[derekblank]

Approved via wordpress-mobile/WordPress-iOS-Shared#352 (review) (pending the Danger checks succeeding and WordPressShared references updating. 😄)

[SiobhyB]

I looked at the last couple of times this reference, which was in #22376 and #20511. From those PRs, I see only the commit hash was updated in the main PR, then apps infra later created a release tag in 7fe3947 and d288944.

@mokagio, is this approach the right one? I've followed that lead with this PR, but would be keen to learn if I should have done something differently here. Thank you!