Fix #6011: Suppress 'switch to app' annoyances by default.

[iccub]

Summary of Changes

This pull request fixes #6011

Submitter Checklist:

• Unit Tests are updated to cover new or changed functionality
• User-facing strings use NSLocalizableString()
• New or updated UI has been tested across:
  • Light & dark mode
  • Different size classes (iPhone, landscape, iPad)
  • Different dynamic type sizes

Test Plan:

1. Fresh install
2. Go to settings -> Brave Shields & Privacy, verify that 'Block 'Switch to App' Notices` is enabled by default.
3. Go to reddit.com, verify that there's no 'switch to mobiel app' showing
4. Disable the setting, go to reddit again and see if the popup is visible

Screenshots:

Reviewer Checklist:

• Issues include necessary QA labels:
  • QA/(Yes|No)
  • bug / enhancement
• Necessary security reviews have taken place.
• Adequate unit test coverage exists to prevent regressions.
• Adequate test plan exists for QA to validate (if applicable).
• Issue and pull request is assigned to a milestone (should happen at merge time).

[cuba]

Looks good...Mostly comments that are not strictly required except that we should remove the UUIDs and add a function that uses componentID