Add blocked channels to search, trending, and recommendations

[mstudio005]

What is it?

• Feature (user facing)

Description of the changes in your PR

• Added a Room database table to store blocked channels with their name and URL
• Added a Blocked Channels screen under Settings → Content
• Added a Block channel option in the video long-press menu with an undo snackbar
• Filtered blocked channels from search results, trending, and related videos
• Fixed a crash on the Blocked Channels settings screen on Android 16
• Fixed a bug where filtering tried to modify immutable lists

Before/After Screenshots/Screen Record

Fixes the following issue(s)

• Fixes Block Channels #12647
• Fixes Blacklist videos, channels and keywords  #1815

Relies on the following changes

• None

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.

Due diligence

• I read the contribution guidelines
• The proposed changes follow the AI policy
• I tested the changes using a physical device (Samsung Galaxy Tab A9+ 5G, Android 16)