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/dependency_test.go

@@ -49,9 +49,13 @@ func TestCreateIssueDependency(t *testing.T) {
 	assert.False(t, left)
 
 	// Close #2 and check again
-	_, err = issues_model.ChangeIssueStatus(db.DefaultContext, issue2, user1, true)
+	_, err = issues_model.CloseIssue(db.DefaultContext, issue2, user1)
 	assert.NoError(t, err)
 
+	issue2Closed, err := issues_model.GetIssueByID(db.DefaultContext, 2)
+	assert.NoError(t, err)
+	assert.True(t, issue2Closed.IsClosed)
+
 	left, err = issues_model.IssueNoDependenciesLeft(db.DefaultContext, issue1)
 	assert.NoError(t, err)
 	assert.True(t, left)
@@ -59,4 +63,11 @@ func TestCreateIssueDependency(t *testing.T) {
 	// Test removing the dependency
 	err = issues_model.RemoveIssueDependency(db.DefaultContext, user1, issue1, issue2, issues_model.DependencyTypeBlockedBy)
 	assert.NoError(t, err)
+
+	_, err = issues_model.ReopenIssue(db.DefaultContext, issue2, user1)
+	assert.NoError(t, err)
+
+	issue2Reopened, err := issues_model.GetIssueByID(db.DefaultContext, 2)
+	assert.NoError(t, err)
+	assert.False(t, issue2Reopened.IsClosed)
 }