Disable fields on save

[etoledom]

Closes GRA-124

Description

This PR is meant to disable the About editor fields while the save request is ongoing.

I tried changing the style of the fields for a visual feedback but there's an issue with the text TextEditor on pre-iOS16

To be able to remove this white background from the text on pre-iOS16, we need to call:
UITextView.appearance().backgroundColor = .clear

Which doesn't seem good to do from an external library.

Testing Steps

• Open the Quick Editor with About editor scope
• Save some changes
  • Check that the fields are disabled while the request is ongoing.

[wpmobilebot]

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

	App Name	Gravatar Prototype Build
	Build Number	2393
	Version	PR #768
	Bundle ID	com.automattic.gravatar-sdk-demo-uikit.prototype-build
	Commit	21a9f6d
	Installation URL	6gm0t9gvv8b70

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

[pinarol]

LGTM 🎉