Use CloseIssue and ReopenIssue instead of ChangeStatus (#32467)

The behaviors of closing issues and reopening issues are very different.
So splitting it into two different functions makes it easier to
maintain.

- [x] Split ChangeIssueStatus into CloseIssue and ReopenIssue both at
the service layer and model layer
- [x] Rename `isClosed` to `CloseOrReopen` to make it more readable.
- [x] Add transactions for ReopenIssue and CloseIssue

---------

Co-authored-by: Zettat123 <zettat123@gmail.com>

models/issues/issue_xref_test.go

@@ -98,7 +98,7 @@ func TestXRef_ResolveCrossReferences(t *testing.T) {
 	i1 := testCreateIssue(t, 1, 2, "title1", "content1", false)
 	i2 := testCreateIssue(t, 1, 2, "title2", "content2", false)
 	i3 := testCreateIssue(t, 1, 2, "title3", "content3", false)
-	_, err := issues_model.ChangeIssueStatus(db.DefaultContext, i3, d, true)
+	_, err := issues_model.CloseIssue(db.DefaultContext, i3, d)
 	assert.NoError(t, err)
 
 	pr := testCreatePR(t, 1, 2, "titlepr", fmt.Sprintf("closes #%d", i1.Index))