[Camera] Add lens type information (iOS)

[lenzpaul]

This PR adds lens type information, which wasn't available before. The goal is to identify whether the lens type is wide, ultra-wide, telephoto, etc., as discussed in flutter/flutter#119908. The iOS implementation is complete, so lens data will now be populated on iOS.

• Introduces a new CameraLensType enum to provide lens type information about the camera (e.g.: ultra-wide, telephoto, ...)
• Adds lensType in the PlatformCameraDescription and CameraDescription classes
• Implements utility functions to convert between PlatformCameraLensType and CameraLensType.
• Updates auto-generated code (using Pigeon) to reflect these changes.

Current CameraDescription for iPhone 11

[
    CameraDescription(
        com.apple.avfoundation.avcapturedevice.built-in_video:0,
        CameraLensDirection.back,
        90
    ),
    CameraDescription(
        com.apple.avfoundation.avcapturedevice.built-in_video:1,
        CameraLensDirection.front,
        90
    ),
    CameraDescription(
        com.apple.avfoundation.avcapturedevice.built-in_video:5,
        CameraLensDirection.back,
        90
    )
]

New CameraDescription for iPhone 11

[
    CameraDescription(
        com.apple.avfoundation.avcapturedevice.built-in_video:0,
        CameraLensDirection.back,
        90,
        CameraLensType.wide
    ),
    CameraDescription(
        com.apple.avfoundation.avcapturedevice.built-in_video:1,
        CameraLensDirection.front,
        90,
        CameraLensType.wide
    ),
    CameraDescription(
        com.apple.avfoundation.avcapturedevice.built-in_video:5,
        CameraLensDirection.back,
        90,
        CameraLensType.ultraWide
    )
]

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene page, which explains my responsibilities.
• I read and followed the relevant style guides and ran the auto-formatter. (Unlike the flutter/flutter repo, the flutter/packages repo does use dart format.)
• I signed the CLA.
• The title of the PR starts with the name of the package surrounded by square brackets, e.g. [shared_preferences]
• I linked to at least one issue that this PR fixes in the description above.
• I updated pubspec.yaml with an appropriate new version according to the pub versioning philosophy, or this PR is exempt from version changes.
• I updated CHANGELOG.md to add a description of the change, following repository CHANGELOG style, or this PR is exempt from CHANGELOG changes.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel on Discord.

[stuartmorgan]

Please see https://github.com/flutter/flutter/blob/master/docs/ecosystem/contributing/README.md#changing-federated-plugins for information on how to make this PR pass CI checks, which is important for review.

[lenzpaul]

Please see https://github.com/flutter/flutter/blob/master/docs/ecosystem/contributing/README.md#changing-federated-plugins for information on how to make this PR pass CI checks, which is important for review.

I made changes as specified by the docs, please let me if there's anything else I need to do

[stuartmorgan]

• All existing and new tests are passing.

This PR is currently failing a substantial number of our CI checks, so this checkbox state is not accurate. If you click through the details of each CI task failure you can see the specific issues that will need to be fixed before this would be ready for review.