visionOS support in MSAL

[mipetriu]

Proposed changes

This PR adds a visionOS target in MSAL and makes a few small changes to allow the code to build and run on visionOS. The most important change is that visionOS no longer supports SafariViewController, so we need to ensure that all references to it are behind OS macros in order for the target to build.

Type of change

• [x] Feature work
• [ ] Bug fix
• [ ] Documentation
• [ ] Engineering change
• [ ] Test
• [ ] Logging/Telemetry

Risk

• [ ] High – Errors could cause MAJOR regression of many scenarios. (Example: new large features or high level infrastructure changes)
• [x] Medium – Errors could cause regression of 1 or more scenarios. (Example: somewhat complex bug fixes, small new features)
• [ ] Small – No issues are expected. (Example: Very small bug fixes, string changes, or configuration settings changes)

Additional information

[frogcjn]

Support this commit. We need SDKs supports visionOS.

[pietbrauer]

@mipetriu Do you have a timeline for this? We would really like to have visionOS support to advance in our prototypes. I tried using this branch with SPM but since it's only downloading the latest release this sadly does not work.

[marcodantonio]

@mipetriu Closed because is working? Write from iPhone, can't check by myself.