[UI Tests] Re-enable media picker tests with support to PHPicker

[tiagomar]

Description

This PR adds support to the new media picker, #21190, and re-enables tests (listed below) impacted by the changes.

EditorGutenbergTests.testAddGalleryBlock()
EditorGutenbergTests.testAddMediaBlocks()
EditorGutenbergTests.testAddRemoveFeaturedImage()
EditorGutenbergTests.testBasicPostPublishWithCategoryAndTag()

Testing

CI should be 🟢

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	App Name	WordPress Alpha
	Configuration	Release-Alpha
	Build Number	pr21447-eeb8693
	Version	23.1
	Bundle ID	org.wordpress.alpha
	Commit	eeb8693
	App Center Build	WPiOS - One-Offs #6884

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[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	pr21447-eeb8693
	Version	23.1
	Bundle ID	com.jetpack.alpha
	Commit	eeb8693
	App Center Build	jetpack-installable-builds #5924

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[kean]

Thank you!

[tiagomar]

The tests failed here because the .nativePhotoPicker Feature Flag is disabled in this branch. 😅 We can see the tests running correctly when merging into trunk.