Make more functions use ctx instead of db.DefaultContext (#24068)

Continue the "ctx refactoring" work.

There are still a lot db.DefaultContext, incorrect context could cause
database deadlock errors.

models/issues/issue_xref_test.go

@@ -83,7 +83,7 @@ func TestXRef_NeuterCrossReferences(t *testing.T) {
 
 	d := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
 	i.Title = "title2, no mentions"
-	assert.NoError(t, issues_model.ChangeIssueTitle(i, d, title))
+	assert.NoError(t, issues_model.ChangeIssueTitle(db.DefaultContext, i, d, title))
 
 	ref = unittest.AssertExistsAndLoadBean(t, &issues_model.Comment{IssueID: itarget.ID, RefIssueID: i.ID, RefCommentID: 0})
 	assert.Equal(t, issues_model.CommentTypeIssueRef, ref.Type)