chore: copy google-cloud-sql from googleapis-gen

[JoeWang1127]

Copy google-cloud-sql from googleapis-gen.

Step to copy the code:

docker run --rm --user $(id -u):$(id -g) -v .:/repo -w /repo -v ../googleapis-gen:/googleapis-gen --env HOME=/tmp gcr.io/cloud-devrel-public-resources/owlbot-cli:latest copy-code  --source-repo=/googleapis-gen --config-file=packages/google-cloud-sql/.OwlBot.yaml

docker run --rm --user $(id -u):$(id -g) -v $(pwd):/repo -w /repo   --env HOME=/tmp   gcr.io/cloud-devrel-public-resources/owlbot-nodejs-mono-repo:latest packages/google-cloud-sql

[gemini-code-assist]

Code Review

This pull request introduces several updates to the Google Cloud SQL Node.js client, including the addition of the ResolveConnectSettings RPC, the new SqlDataService for bidirectional SQL data streaming, and various new configuration fields (such as performance capture thresholds and accelerated replica mode). However, the reviewer noted a critical issue: several newly exported service clients in both v1 and v1beta4 index files are missing their corresponding implementation files, which will lead to compilation and build failures.