Fix #4335: Deprecate ours HTTPSE in favor of the one bundled in WKWeb…

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Summary of Changes

Security review https://github.com/brave/security/issues/640

This pull request fixes #4335

Submitter Checklist:

• Unit Tests are updated to cover new or changed functionality
• User-facing strings use NSLocalizableString()

Test Plan:

Note for testers: this feature has been enabled on iOS 15 devices by default, we kept using Apple's and our implementation for some time.

This is a simple flag we turn on, we can't decide what websites are upgraded or not, we do not also know what websites we can test this on. I found apache.org to be a good candidate for testing.

Use iOS 15 device.
Enabled case:

• Go to http://apache.org or enter apache.org in url bar
• Verify that the website upgraded itself to https

Disabled case:

• Go to Brave settings -> Shields and disable HTTPS upgrades
• Go to http://apache.org or enter apache.org in url bar
• Verify that the website did not upgrade to https

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).