Terraform lint to compare endpoints to charmcraft.yaml

In addition to `fmt` and `validate` we should confirm a 1:1 match between the `endpoints` output and charmcraft.yaml, to avoid surprise PRs such as https://github.com/canonical/traefik-k8s-operator/pull/497.

https://github.com/canonical/observability/blob/200d85bf167c9ebad8d51f745ade62016a4d23f9/.github/workflows/_charm-quality-checks.yaml#L120-L121

Start with .github/workflows/_charm-quality-checks.yaml at the referenced lines, alongside the existing fmt and validate checks. Determine how the workflow obtains the endpoints output and compares it with charmcraft.yaml; the work is done when the lint rejects any mismatch and accepts a 1:1 match.

Written by the indexing model from the issue text.