**Apache Airflow version**: 2.1.0

**Browsers**: Chrome and Firefox

**What happened**:

Before upgrading to 2.1.0

![before](https://user-images.githubusercontent.com/14293802/120359517-c1ca1100-c2d5-11eb-95ba-58ccc0a3ac37.png)

After upgrading to 2.1.0

![after](https://user-images.githubusercontent.com/14293802/120359528-c4c50180-c2d5-11eb-8e04-f34846ea2736.png)

**What you expected to happen**:

Show/Edit/Delete under Security -> Users are available

<!-- What do you think went wrong? -->

**How to reproduce it**:

Go to Security -> Users (as an admin of course) 
airflow/www/views.py
match = re.search(r"_copy(\d+)$", selected_conn.conn_id)
            if match:
                conn_id_prefix = selected_conn.conn_id[: match.start()]
                new_conn_id = f"{conn_id_prefix}_copy{int(match.group(1)) + 1}"
            else:
                new_conn_id += '_copy1'
            dup_conn = Connection(
                new_conn_id,
                selected_conn.conn_type,
                selected_conn.description,
                selected_conn.host,
                selected_conn.login,
                selected_conn.password,
                selected_conn.schema,
                selected_conn.port,
                selected_conn.extra,
            )
            try:
                session.add(dup_conn)
                session.commit()
                flash(f"Connection {new_conn_id} added successfully.", "success")
            except IntegrityError:
                flash(
                    f"Connection {new_conn_id} can't be added. Integrity error, probably unique constraint.",
                    "warning",
                )
                session.rollback()
        self.update_redirect()
        return redirect(self.get_redirect())
    def process_form(self, form, is_created):