Remove livekit WebRTC-SDK podspec workaround once upstream aligns

[Deniel9204]

Problem

flutter_webrtc and livekit_client are both pinned to ref: hkdf (moving branches) and their current heads declare incompatible WebRTC-SDK versions, so CocoaPods can't resolve and the macOS (and iOS) build fails at pod install:

plugin	hkdf podspec	WebRTC-SDK
flutter_webrtc	2d0dce5e	144.7559.04
livekit_client	19f6b86d	144.7559.01

This affects upstream commet too (identical pubspec). pod repo update does not fix it — the conflict is in the plugins' podspecs.

Workaround applied (this repo)

commet/macos/Podfile rewrites livekit's WebRTC-SDK pin 144.7559.01 -> 144.7559.04 at pod-install time (the two are the same m144 milestone, so they're compatible). This unblocks the macOS build with no manual steps.

Proper fix (remove the workaround when done)

• Ideal: upstream commetchat/livekit-client-sdk-flutter bumps WebRTC-SDK on hkdf to match flutter_webrtc (.04), or both plugin refs are pinned to a coordinated commit pair; then delete the Podfile snippet.
• If iOS builds are added, apply the same patch to the iOS podspec.

Acceptance: macOS pod install resolves without the Podfile workaround.

[Deniel9204]

Workaround landed in #197 (commet/macos/Podfile). This issue tracks removing it once upstream aligns the two plugins' WebRTC-SDK versions.