REST API: Migrate inbox note endpoints

[itsmeichigo]

Closes: #8639

Description

This PR updates the mappers for inbox notes and enable REST API for the related endpoints.

Testing instructions

Pre-requisite: due to a rate-limit issue with Pressable sites, create a JN site to ensure that testing is smooth for now.

• Enable feature flag applicationPasswordAuthenticationForSiteCredentialLogin and build the app.
• Log out of the app or skip onboarding if needed.
• On the prologue screen, select Enter your site address and enter the address of your self-hosted site.
• Proceed to log in with site credentials.
• When the login succeeds, you should see the home screen.
• Navigate to the Menu tab and select Inbox. Notice that a list of notes is loaded.
• Tap the action button on an item, notice that the item is marked as read without error (there should be no error logged in Xcode console ⛔️ Error on mark inbox note as actioned).
• Tap the Dismiss button on an item, the item should be dismissed without error.
• Tap the ellipsis button on the top right of the inbox list and select Dismiss all. All notes should be dismissed without error.
• Navigate out of the inbox screen and back in. The list should still be empty.

Screenshots

Simulator.Screen.Recording.-.iPhone.14.Pro.-.2023-01-16.at.12.11.13.mp4

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• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[wpmobilebot]

You can test the changes from this Pull Request by:

• Clicking here or scanning the QR code below to access App Center
• Then installing the build number pr8641-809c371 on your iPhone

If you need access to App Center, please ask a maintainer to add you.

[jaclync]

LGTM

Non-blocking note: it'd be nice if the links can be authenticated by default in the webview, like how we do for WPCOM credentials. For example, when opening the action with URL {{site_url}}/wp-admin/admin.php?page=wc-addons&section=helper it shows the login page:

Even though Inbox hasn't been launched, this improvement might benefit some other AuthenticatedWebview use cases as well.

[itsmeichigo]

it'd be nice if the links can be authenticated by default in the webview, like how we do for WPCOM credentials.

Great point, thanks for the suggestion @jaclync. I've created a separate issue for this enhancement in #8643.