fix: make prometheus image variable dynamic

[cbid71]

No description provided.

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[amandakarina]

/gcbrun

[amandakarina]

Linting is failing:

2026/04/14 16:26:56 
Checking for documentation generation
diff -r '--exclude=.terraform' '--exclude=.kitchen' '--exclude=autogen' '--exclude=*.tfvars' '--exclude=*metadata.yaml' /workspace/modules/v2/README.md /tmp/tmp.1YE2XvCIyk/generate_docs/workspace/modules/v2/README.md
71a72
> | prometheus\_sidecar\_image | Image associated to the Prometheus sidecar. | `string` | `"us-docker.pkg.dev/cloud-ops-agents-artifacts/cloud-run-gmp-sidecar/cloud-run-gmp-sidecar:1.1.1"` | no |
Error: Documentation generation has not been run, please run the
'make docker_generate_docs' command and commit the above changes.

[cbid71]

ok I've played make docker_generate_docs