fix app crash on loading comment section with no internet

[Idadelveloper]

What is it?

• Bugfix (user facing)
• Feature (user facing) ⚠️ Your PR must target the refactor branch
• Codebase improvement (dev facing)
• Meta improvement to the project (dev facing)

Description of the changes in your PR

Fix crash when scrolling the comment section without internet by catching exceptions in CommentsSource.load() and returning LoadResult.Error, and handle the paging append error state in CommentSection to show an error panel with a retry button.

Before/After Screenshots/Screen Record

• Before:
• After:

Fixes the following issue(s)

• Fixes #

APK testing

The APK can be found by going to the "Checks" tab below the title. On the left pane, click on "CI", scroll down to "artifacts" and click "app" to download the zip file which contains the debug APK of this PR. You can find more info and a video demonstration on this wiki page.

Due diligence

• I read the contribution guidelines.
• The proposed changes follow the AI policy.
• I tested the changes using an emulator or a physical device.