Update Aztec to use new media pickers (requires Xcode 15)

[kean]

This is one of the remaining prerequisites for fully decommissioning WPMediaPicker.

Note: this PR requires Xcode 15; please test it locally.

Changes

• Integrate SiteMediaPickerViewController for selection from your site media
• Integrate PHPickerViewController for selection from Photos
• Use UIImagePickerController for camera capture
• Use PHPickerViewController to replace the embedded picker. It’s available only on iOS 17, which I think is an acceptable trade-off, considering the extremely low number of Aztec users and people who use this option. The iOS 17 adoption has been lagging behind, but by the time this release I expect at least 50% of users to be on iOS 17. I considered implementing a custom picker using Photos.framework and PHAsset, but since the app no longer asks for Photos permissions anywhere else, I don't think it's viable. It also would've required full access to Photos (not "Only Selected")

To test:

Prerequisite: In EditorFactory.swift, update EditorFactory instantiateEditor` to always return Aztec.

Embedded picker

Inserting Media

• Select images, videos from the embedded picker
• Upload the post and verify that the items were displayed
• Upload a GIF image and verify that the editor displayed a "GIF" badge

Keyboard Toolbar

• Open embedded picker
• Select a couple of assets
• Verify that the “Insert X” keyboard toolbar button is continuously updated as items are selected
• Press “Cancel” (little “x”)
• Verify that the embedded picker is dismissed
• Open the picker again
• Verify that the keyboard toolbar button for inserting assets no longer shows “Insert X” (selected was cleared)

iOS 16 and Earlier

• Verify that inline picker is not displayed on iOS 16 or earlier
• Verify that you can still toggle between "Text" and "Media" modes

Camera

• Verify that you can capture images and videos using "Camera"

Photos

• Verify that the new picker is used PHPickerViewController
• Verify that images and videos can be selected and added to the post
• Verify that "Cancel" dismissed the picker

Site Media

• Verify that the new picker is used PHPickerViewController
• Verify that images , videos, and documents can be selected and added to the post
• Verify that "Cancel" dismissed the picker (known issue: Fix an issue with cancel not working correctly in site media picker #22041)

Regression Notes

1. Potential unintended areas of impact: Aztec (Classic Editor)
2. What I did to test those areas of impact (or what existing automated tests I relied on): manual;
3. What automated tests I added (or what prevented me from doing so): n/a

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.

UI Changes testing checklist:

• 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)

[kean]

FYI, @twstokes.

[kean]

Hey, @mokagio. What's the timeline for switching to Xcode 15? This PR requires iOS 17 SDK.

[momo-ozawa]

Works as described! 1 small thing - I'm not sure if this is an iOS 17 issue, or a simulator issue, but when I launch the Aztec editor the toolbar is partially obscured. I think normally this shouldn't be a problem because the keyboard will be displayed underneath the toolbar, but thought it may be worth mentioning

[twstokes]

FYI, @twstokes.

This is awesome. Thank you!

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📲 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	pr22060-dc03e76
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📲 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	pr22060-dc03e76
	Version	23.7
	Bundle ID	com.jetpack.alpha
	Commit	dc03e76
	App Center Build	jetpack-installable-builds #6988

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