fix: remove artificial delay for PR update (#7773)

- I was not able to find a reasoning in the pull request (https://github.com/go-gitea/gitea/pull/9784) for the existence of this `time.Sleep`. The best I could come up with during manual testing is that there's a brief moment where 'this pull request is missing fork information' is shown, this was caused by an incorrect condition.
- Added integration test.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/7773
Reviewed-by: 0ko <0ko@noreply.codeberg.org>
Reviewed-by: Otto <otto@codeberg.org>
Co-authored-by: Gusted <postmaster@gusted.xyz>
Co-committed-by: Gusted <postmaster@gusted.xyz>

tests/integration/pull_update_test.go

@@ -273,3 +273,19 @@ func createOutdatedPR(t *testing.T, actor, forkOrg *user_model.User) *issues_mod
 
 	return issue.PullRequest
 }
+
+func TestStatusDuringUpdate(t *testing.T) {
+	onGiteaRun(t, func(t *testing.T, u *url.URL) {
+		session := loginUser(t, "user2")
+
+		// Adjust this pull request to be in the conflict checker and having a head
+		// branch that is pointing to the an incorrect commit ID.
+		_, err := db.GetEngine(t.Context()).Cols("status", "head_branch").Update(&issues_model.PullRequest{ID: 5, Status: issues_model.PullRequestStatusChecking, HeadBranch: "master"})
+		require.NoError(t, err)
+
+		resp := session.MakeRequest(t, NewRequest(t, "GET", "/user2/repo1/pulls/5"), http.StatusOK)
+		htmlDoc := NewHTMLParser(t, resp.Body)
+
+		assert.Contains(t, htmlDoc.Find(".merge-section .item").Text(), "Merge conflict checking is in progress. Try again in few moments.")
+	})
+}