This pull request is adding functionality of Biometric - Pin Code local authentication to Tab Mode Changer. It is controlled by toggle in Settings that indicates Private Browsing should be woking under local authentication and on by default also can be switched off by will of users.

The placement of the toggle changed with #7868 so please check out using information there.

Summary of Changes

This pull request fixes #7810

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:

Step 1

• Navigate Settings and check there is new entry and toggle for "Private Browsing Lock"
• Check the toggle is enabled by default

Step 2

• Navigate back to tab tray and press private button enable private mode
• Check biometric authentication is presented
• Test various scenarios like successful id - unsuccessful id and cancel / unlock again permutations

Step 3

• Validate going to normaa mode while private mode is active doesnt ask for biometrics

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).