chore: Make objc a workspace level crate (#28258)

Make objc a workspace level crate to unify version control

Release Notes:

- N/A

crates/livekit_client/Cargo.toml

@@ -52,7 +52,7 @@ scap.workspace = true
 core-foundation.workspace = true
 core-video.workspace = true
 coreaudio-rs = "0.12.1"
-objc = "0.2"
+objc.workspace = true
 
 [dev-dependencies]
 collections = { workspace = true, features = ["test-support"] }