**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
"""Set state to failed."""
        try:
            count = 0
            altered_tis = []
            for dr in session.query(DagRun).filter(DagRun.id.in_([dagrun.id for dagrun in drs])).all():
                count += 1
                altered_tis += set_dag_run_state_to_failed(
                    current_app.dag_bag.get_dag(dr.dag_id), dr.execution_date, commit=True, session=session
                )
            altered_ti_count = len(altered_tis)
            flash(
                "{count} dag runs and {altered_ti_count} task instances "
                "were set to failed".format(count=count, altered_ti_count=altered_ti_count)
            )
        except Exception:
            flash('Failed to set state', 'error')
        return redirect(self.get_default_url())
    @action(
        'set_success',
        "Set state to 'success'",
        "All task instances would also be marked as success, are you sure?",
        single=False,
    )
    @provide_session
    def action_set_success(self, drs, session=None):