Update grpc to v1.55.0

This fixes a number of Ruby 3.1 and 3.2 issues. It also fixes a GitLab
build issue on ArchLinux: https://bugs.archlinux.org/task/78379

Release notes:

* https://github.com/grpc/grpc/releases/tag/v1.43.0
* https://github.com/grpc/grpc/releases/tag/v1.44.0
* https://github.com/grpc/grpc/releases/tag/v1.45.0
* https://github.com/grpc/grpc/releases/tag/v1.46.0
* https://github.com/grpc/grpc/releases/tag/v1.47.0
* https://github.com/grpc/grpc/releases/tag/v1.48.0
* https://github.com/grpc/grpc/releases/tag/v1.49.0
* https://github.com/grpc/grpc/releases/tag/v1.50.0
* https://github.com/grpc/grpc/releases/tag/v1.51.0
* https://github.com/grpc/grpc/releases/tag/v1.52.0
* https://github.com/grpc/grpc/releases/tag/v1.53.0
* https://github.com/grpc/grpc/releases/tag/v1.54.0
* https://github.com/grpc/grpc/releases/tag/v1.55.0

Full diff: https://github.com/grpc/grpc/compare/v1.42.0..v1.55.0

https://github.com/grpc/grpc/pull/29869 added braces around the
`debug_error_string`, so just strip these out.

Changelog: changed