Remove commit status running and warning to align GitHub (#25839)

Fix #25776. Close #25826.

In the discussion of #25776, @wolfogre's suggestion was to remove the
commit status of `running` and `warning` to keep it consistent with
github.

references:
-
https://docs.github.com/en/rest/commits/statuses?apiVersion=2022-11-28#about-commit-statuses


## ⚠️ BREAKING ⚠️

So the commit status of Gitea will be consistent with GitHub, only
`pending`, `success`, `error` and `failure`, while `warning` and
`running` are not supported anymore.

---------

Co-authored-by: Jason Song <i@wolfogre.com>

models/migrations/migrations.go

@@ -513,6 +513,8 @@ var migrations = []Migration{
 	NewMigration("Add branch table", v1_21.AddBranchTable),
 	// v265 -> v266
 	NewMigration("Alter Actions Artifact table", v1_21.AlterActionArtifactTable),
+	// v266 -> v267
+	NewMigration("Reduce commit status", v1_21.ReduceCommitStatus),
 }
 
 // GetCurrentDBVersion returns the current db version