Disable API breakage check in pull request workflow

[ktoso]

This package is not stable, so no need for those checks

[ktoso]

Hmm, lots of timeouts downloading protobuf

Run /usr/bin/xcodebuild -quiet -scheme ${BUILD_SCHEME} -destination "generic/platform=macos,variant=macos" build
2025-09-08 02:15:35.246 xcodebuild[73049:684173] Writing error result bundle to /var/folders/wp/s229xdvs6mb4dn4bmch1tjtw0000gp/T/ResultBundle_2025-08-09_02-15-0035.xcresult
xcodebuild: error: Could not resolve package dependencies:
  failed downloading 'https://github.com/apple/swift-protobuf/releases/download/protoc-artifactbundle-v31.1/protoc-31.1.artifactbundle.zip' which is required by binary target 'protoc': downloadError("The request timed out.")