bug: unify RepoActionRun and ActionRun structs (#8250)

Two pull requests were merged at the same time

- https://codeberg.org/forgejo/forgejo/pulls/7699
- https://codeberg.org/forgejo/forgejo/pulls/7508

And added conflicting structs ActionRun modules/structs.  That broke
the forgejo development branch and a quick fix was made to resolve
the name conflict.

- https://codeberg.org/forgejo/forgejo/pulls/8066

However that creates an undesirable duplication of two structures that
serve the same purpose but are different.

- Remove RepoActionRun and replace it with ActionRun
- convert.ToActionRun has one more argument, the doer, because it
  is determined differently in the context of webhooks or API

### Tests

- No need because the two pull requests involved already have good coverage.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/8250
Reviewed-by: Michael Kriese <michael.kriese@gmx.de>
Reviewed-by: klausfyhn <klausfyhn@noreply.codeberg.org>
Reviewed-by: Christopher Besch <mail@chris-besch.com>
Co-authored-by: Earl Warren <contact@earl-warren.org>
Co-committed-by: Earl Warren <contact@earl-warren.org>

modules/structs/repo_actions.go

@@ -32,23 +32,3 @@ type ActionTaskResponse struct {
 	Entries    []*ActionTask `json:"workflow_runs"`
 	TotalCount int64         `json:"total_count"`
 }
-
-// ActionRun represents an ActionRun
-type RepoActionRun struct {
-	ID              int64  `json:"id"`
-	Name            string `json:"name"`
-	RunNumber       int64  `json:"run_number"`
-	Event           string `json:"event"`
-	Status          string `json:"status"`
-	HeadBranch      string `json:"head_branch"`
-	HeadSHA         string `json:"head_sha"`
-	WorkflowID      string `json:"workflow_id"`
-	URL             string `json:"url"`
-	TriggeringActor *User  `json:"triggering_actor"`
-}
-
-// ListActionRunResponse return a list of ActionRun
-type ListRepoActionRunResponse struct {
-	Entries    []*RepoActionRun `json:"workflow_runs"`
-	TotalCount int64            `json:"total_count"`
-}