Extract build phase to copy Gutenberg resources in script

[mokagio]

I run into this script while working on #20717, when it failed because the Pods/Gutenberg/bundle/ios folder was no longer there.

I am not sure how much of this script will be necessary with the XCFramework setup, but I have a feeling at least some of it will. In such case, we can benefit from centralizing it so that we can more easily modify it when the time comes.

For what is worth, any build phase run script can benefit from being extracted in a dedicated file. The Xcode run script text view is not a good medium where to write code. 😅

Testing

I run the app in the Simulator and verified the block editor loaded and that images were there. Can you think of anything else?

Regression Notes

1. Potential unintended areas of impact – N.A.
2. What I did to test those areas of impact (or what existing automated tests I relied on) – N.A.
3. What automated tests I added (or what prevented me from doing so) – N.A.

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PR submission checklist:

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

UI changes testing checklist: Not a UI PR.

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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	pr20719-e345b84
	Version	22.4
	Bundle ID	org.wordpress.alpha
	Commit	e345b84
	App Center Build	WPiOS - One-Offs #5743

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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	pr20719-e345b84
	Version	22.4
	Bundle ID	com.jetpack.alpha
	Commit	e345b84
	App Center Build	jetpack-installable-builds #4773

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[dcalhoun]

Relocating this makes sense to me. 🚀

I verified the block editor loaded, including local images found within the editor:

1. Tap the three-dot menu in the top-right corner.
2. Tap Help & Support.
3. Navigate to a help article.