Code Review Bench PR #31468 - Refactor FXIOS-14466 FXIOS-14463 [Swift 6 Migration] Migrate ShareTo and BrowserKit Package to Swift 6

[tomerqodo]

Code Review Bench PR mozilla-mobile#31468

Original PR Title: Refactor FXIOS-14466 FXIOS-14463 [Swift 6 Migration] Migrate ShareTo and BrowserKit Package to Swift 6
Original PR Description: ## 📜 Tickets
FXIOS-14466
FXIOS-14463

💡 Description

• Migrate ShareTo to Swift 6.
• Migrate entire BrowserKit package to Swift 6.2.
• Cleanup BrowserKit Package file now that experimental/upcoming features are enabled in Swift 6.2 by default.

No warnings as far as I can tell... let's see what Bitrise says.

📝 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 adding or modifying strings, I read the guidelines and will request a string review from l10n
• If needed, I updated documentation and added comments to complex code

Original PR URL: mozilla-mobile#31468