feat: make it possible to remove workflow runs (#12478)

Add the ability to remove workflow runs, either using the UI or the HTTP API. Workflow runs can only be removed once a workflow run has completed. For security reasons, only a repository administrator or a token with `write:repository` permissions can remove runs.

Resolves https://codeberg.org/forgejo/forgejo/issues/2184.

## Checklist

The [contributor guide](https://forgejo.org/docs/next/contributor/) contains information that will be helpful to first time contributors. All work and communication must conform to Forgejo's [AI Agreement](https://codeberg.org/forgejo/governance/src/branch/main/AIAgreement.md). There also are a few [conditions for merging Pull Requests in Forgejo repositories](https://codeberg.org/forgejo/governance/src/branch/main/PullRequestsAgreement.md). You are also welcome to join the [Forgejo development chatroom](https://matrix.to/#/#forgejo-development:matrix.org).

### Tests for Go changes

(can be removed for JavaScript changes)

- I added test coverage for Go changes...
  - [x] in their respective `*_test.go` for unit tests.
  - [x] in the `tests/integration` directory if it involves interactions with a live Forgejo server.
- I ran...
  - [x] `make pr-go` before pushing

### Tests for JavaScript changes

(can be removed for Go changes)

- I added test coverage for JavaScript changes...
  - [ ] in `web_src/js/*.test.js` if it can be unit tested.
  - [ ] in `tests/e2e/*.test.e2e.js` if it requires interactions with a live Forgejo server (see also the [developer guide for JavaScript testing](https://codeberg.org/forgejo/forgejo/src/branch/forgejo/tests/e2e/README.md#end-to-end-tests)).

### Documentation

- [ ] I created a pull request [to the documentation](https://codeberg.org/forgejo/docs) to explain to Forgejo users how to use this change.
- [x] I did not document these changes and I do not expect someone else to do it.

### Release notes

- [x] This change will be noticed by a Forgejo user or admin (feature, bug fix, performance, etc.). I suggest to include a release note for this change.
- [ ] This change is not visible to a Forgejo user or admin (refactor, dependency upgrade, etc.). I think there is no need to add a release note for this change.

*The decision if the pull request will be shown in the release notes is up to the mergers / release team.*

The content of the `release-notes/<pull request number>.md` file will serve as the basis for the release notes. If the file does not exist, the title of the pull request will be used instead.

<!--start release-notes-assistant-->

## Release notes
<!--URL:https://codeberg.org/forgejo/forgejo-->
- Features
  - [PR](https://codeberg.org/forgejo/forgejo/pulls/12478): <!--number 12478 --><!--line 0 --><!--description bWFrZSBpdCBwb3NzaWJsZSB0byByZW1vdmUgd29ya2Zsb3cgcnVucw==-->make it possible to remove workflow runs<!--description-->
<!--end release-notes-assistant-->

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/12478
Reviewed-by: Mathieu Fenniak <mfenniak@noreply.codeberg.org>

routers/api/v1/api.go

@@ -450,9 +450,16 @@ func reqSelfOrAdmin() func(ctx *context.APIContext) {
 	}
 }
 
-// reqAdmin user should be an owner or a collaborator with admin write of a repository, or site admin
-func reqAdmin() func(ctx *context.APIContext) {
+// reqAdmin user should be an owner or a collaborator with admin write of a repository, or site admin. If one or more
+// unitTypes are given, it also requires that at least one the respective unitTypes is enabled.
+func reqAdmin(unitTypes ...unit.Type) func(ctx *context.APIContext) {
 	return func(ctx *context.APIContext) {
+		if len(unitTypes) > 0 && !slices.ContainsFunc(unitTypes, func(unitType unit.Type) bool {
+			return ctx.Repo.Repository.UnitEnabled(ctx, unitType)
+		}) {
+			ctx.NotFound()
+			return
+		}
 		if !ctx.IsUserRepoAdmin() && !ctx.IsUserSiteAdmin() {
 			ctx.Error(http.StatusForbidden, "reqAdmin", "user should be an owner or a collaborator with admin write of a repository")
 			return
@@ -1245,6 +1252,7 @@ func Routes() *web.Route {
 					m.Group("/runs", func() {
 						m.Get("", repo.ListActionRuns)
 						m.Get("/{run_id}", repo.GetActionRun)
+						m.Delete("/{run_id}", reqToken(), reqAdmin(unit.TypeActions), repo.DeleteActionRun)
 						m.Get("/{run_id}/jobs", repo.ListActionRunJobs)
 						m.Get("/{run_id}/artifacts", repo.ListActionRunArtifacts)
 					})