Upgrade mobile_scanner to ^7.0.0 to restore arm64 iOS Simulator support

[zolero]

Upgrade mobile_scanner to ^7.1.4 to restore arm64 iOS Simulator support

This PR upgrades the mobile_scanner dependency in the qr_scanner module from ^6.0.11 to ^7.1.4.

The previous version relied on MLKit for iOS barcode/QR scanning, which does not support arm64 architecture on iOS Simulators (Apple Silicon Macs). This caused build and runtime failures when targeting arm64 simulators.

Starting with mobile_scanner v7.0.0, MLKit has been deprecated on iOS in favor of Apple’s native Vision API, which:

• Restores full support for arm64 iOS Simulators
• Aligns iOS with the existing macOS Vision implementation
• Lowers the minimum iOS deployment target back to Flutter’s default (12.0)
• Improves performance and reliability

Changes

• Updated modules/qr_scanner/pubspec.yaml:

  dependencies:
    mobile_scanner: ^7.1.4
    

Impact

Fixes build failures on arm64 iOS Simulators (M1/M2/M3/M4 Macs)

Removes the need for Rosetta, physical devices, or architecture exclusions

Closes #2152

[zolero]

Could this be updated @sharjeelyunus, it's blocking our release for our company.