Fix bug in getting merged pull request by commit (#32079)

routers/api/v1/api.go

@@ -1286,6 +1286,8 @@ func Routes() *web.Router {
 					m.Group("/{ref}", func() {
 						m.Get("/status", repo.GetCombinedCommitStatusByRef)
 						m.Get("/statuses", repo.GetCommitStatusesByRef)
+					}, context.ReferencesGitRepo())
+					m.Group("/{sha}", func() {
 						m.Get("/pull", repo.GetCommitPullRequest)
 					}, context.ReferencesGitRepo())
 				}, reqRepoReader(unit.TypeCode))