Bugfix FXIOS-9909 [Content Sharing] Block open external apps (backport #26341)

[mergify]

📜 Tickets

Jira ticket
Github issue

💡 Description

Bugfix block open external apps with special WKNavigationActionPolicy private case, which stands for allowBlockingUniversalLinks. Remove TabNavigationManagerDelegate since it was adding a layer on top of WKNavigationDelegate which were resulting in the BrowserViewController having not direct influence on the navigation, since for delayed response the TabNavigationManagerDelegate would respond before the browser.

Now as discussed with @afurlan-firefox we have the same behavior of other browsers, that by default we open external apps without user asking, but we block for all privates tabs. Still the user can block all the apps, by turning on the appropriate setting.

🎥 Demos

ScreenRecording_04-28-2025.15-07-55_1.MP4

📝 Checklist

• I filled in the ticket numbers and a description of my work
• I updated the PR name to follow our PR naming guidelines
• I ensured unit tests pass and wrote tests for new code
• If working on UI, I checked and implemented accessibility (Dynamic Text and VoiceOver)
• If adding telemetry, I read the data stewardship requirements and will request a data review
• If needed, I updated documentation and added comments to complex code
• If needed, I added a backport comment (example @Mergifyio backport release/v120)

---

This is an automatic backport of pull request #26341 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 8553936 has failed:

On branch mergify/bp/release/v138/pr-26341
Your branch is up to date with 'origin/release/v138'.

You are currently cherry-picking commit 855393657.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   firefox-ios/Client/Frontend/Browser/BrowserViewController/Views/BrowserViewController.swift
	modified:   firefox-ios/Client/TabManagement/TabManager.swift
	deleted:    firefox-ios/Client/TabManagement/TabManagerNavDelegate.swift
	modified:   firefox-ios/firefox-ios-tests/Tests/ClientTests/Frontend/Browser/BrowserViewControllerWebViewDelegateTests.swift
	modified:   firefox-ios/firefox-ios-tests/Tests/ClientTests/Mocks/MockTabManager.swift

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	both modified:   firefox-ios/Client.xcodeproj/project.pbxproj
	both modified:   firefox-ios/Client/Frontend/Browser/BrowserViewController/Extensions/BrowserViewController+WebViewDelegates.swift
	both modified:   firefox-ios/Client/TabManagement/TabManagerImplementation.swift
	deleted by them: firefox-ios/firefox-ios-tests/Tests/ClientTests/TabManagement/Legacy/TabManagerNavDelegateTests.swift

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally