chore: enable generation for gapic-generator

[parthea]

This PR re-enables generation for gapic-generator which was temporarily skipped due to #16863

This PR was created using

export V=v0.11.0
go run github.com/googleapis/librarian/tool/cmd/builddockerimages@${V} --version ${V} --language python
docker run -u $(id -u):$(id -g) -v .:/repo -v ~/.cache:/.cache -w /repo docker.io/library/librarian-python:${V} generate -v gapic-generator

[gemini-code-assist]

Code Review

This pull request removes the 'skip_generate' flag for the gapic-generator in librarian.yaml and deletes the 'name_pretty' field from the .repo-metadata.json file. The reviewer suggests retaining the 'name_pretty' field to ensure the package maintains a human-readable title in documentation and discovery services.

[gemini-code-assist]

The name_pretty field is used to provide a human-readable title for the package in documentation and discovery services. Removing it will likely cause the package to be listed by its technical name (gapic-generator) rather than the descriptive "Google API Client Generator for Python". Unless this removal is intentional, it should be retained to maintain metadata quality and discoverability.

Suggested change

	"release_level": "stable",
	"name_pretty": "Google API Client Generator for Python",
	"release_level": "stable",