Error if assigning a "UTF-8" string with invalid UTF-8.

This has been a warning since v28.x: https://github.com/protocolbuffers/protobuf/commit/fa8dbaec865508e85a24e71aa652dd9a30ada657

See also https://protobuf.dev/news/2024-10-02/#utf-8-enforcement which pre-announces this for v30.x.

Fixes https://github.com/protocolbuffers/protobuf/issues/17484

PiperOrigin-RevId: 691917648

Sandy Zhang committed 1y ago

2f505a7aa1c7012d3867caa012c310b5da4c33d2

Parent: 7521732

Committed by Copybara-Service <copybara-worker@google.com> on 10/31/2024, 8:47:55 PM