Make ci-infra-service.yml work with multiple apps

[lorenyu]

infra/test/infra_test.go does not currently support multiple apps. It currently hardcodes app. to make it support multiple apps we will want to:

1. separate the test into infra/test/<app_name>/infra_test.go
2. extract the logic from .github/workflows/ci-infra-service.yml into a new callable workflow infra-test-app.yml (similar to deploy.yml and vulnerability-scans.yml)
3. make .github/workflows/ci-infra-<app_name>.yml that calls the callable workflow

[lorenyu]

@rocketnova fyi since you're working on multi-app stuff. ci-infra-service.yml can probably be out of scope for your multi-app scripts since it needs to be refactored before it can be supported.

[lorenyu]

cc @doshitan you could theoretically work on this too