chore: revert iOS deployment target to 13 in stencil

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: pblazej

scripts/Package.swift.stencil

@@ -6,7 +6,7 @@ import PackageDescription
 let package = Package(
     name: "LiveKit",
     platforms: [
-        .iOS(.v14),
+        .iOS(.v13),
         .macOS(.v10_15),
         .macCatalyst(.v14),
         .tvOS(.v17),