[video_player_avfoundation] Add adaptive bitrate streaming support

[sheershtehri7]

Implements adaptive bitrate streaming support for the iOS/macOS video player.

Changes

• setBandwidthLimit — Implements the platform interface method via AVPlayerItem.preferredPeakBitRate. A value of 0 tells AVFoundation to use its default (no cap), letting the player choose quality freely. Positive values limit the peak bitrate in bits per second.

This is the idiomatic AVFoundation approach — preferredPeakBitRate is a first-class property on AVPlayerItem that controls which HLS/DASH variant the player selects.

Versioned as 2.10.0 — minor version bump. Requires video_player_platform_interface ^6.7.0.

Depends on PR #11322 (platform interface setBandwidthLimit).

Part of flutter/flutter#183941

AI Disclosure: This PR was developed with assistance from AI tools (GitHub Copilot / Claude). All code has been reviewed, tested, and validated by the author.

Pre-Review Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the AI contribution guidelines and understand my responsibilities, or I am not using AI tools.
• I read the Tree Hygiene page, which explains my responsibilities.
• I read and followed the relevant style guides and ran the auto-formatter.
• 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 followed the version and CHANGELOG instructions, using semantic versioning and the repository CHANGELOG style, or I have commented below to indicate which documented exception this PR falls under¹.
• I updated/added any relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or I have commented below to indicate which test exemption this PR falls under¹.
• All existing and new tests are passing.

Footnotes

1. Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling. ↩ ↩²

[gemini-code-assist]

Code Review

This pull request adds support for adaptive bitrate streaming on iOS and macOS by implementing the setBandwidthLimit method. This is achieved by setting the preferredPeakBitRate property on AVPlayerItem. The changes include updates to the Pigeon interface definition, the native Objective-C implementation, the Dart plugin code, and associated tests. One review comment has been added regarding error handling in the native implementation.

[gemini-code-assist]

Using NSAssert is great for debugging, but it's disabled in release builds. If currentItem is nil in a release build, this method will silently do nothing, which could lead to unexpected behavior. It would be more robust to check for a nil currentItem and return an error, ensuring consistent behavior across build configurations.

if (!currentItem) {
  *error = [FlutterError errorWithCode:@"no_player_item"
                               message:@"The player has no current item."
                               details:nil];
  return;
}

[stuartmorgan-g]

Closing per #11322 (comment)