**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
"""Last DAG runs"""
        allowed_dag_ids = current_app.appbuilder.sm.get_accessible_dag_ids(g.user)
        
        selected_dag_ids = {unquote(dag_id) for dag_id in request.form.getlist('dag_ids') if dag_id}
        if selected_dag_ids:
            filter_dag_ids = selected_dag_ids.intersection(allowed_dag_ids)
        else:
            filter_dag_ids = allowed_dag_ids
        if not filter_dag_ids:
            return wwwutils.json_response({})
        query = session.query(
            DagRun.dag_id,
            sqla.func.max(DagRun.execution_date).label('execution_date'),
            sqla.func.max(DagRun.start_date).label('start_date'),
        ).group_by(DagRun.dag_id)
        
        query = query.filter(DagRun.dag_id.in_(filter_dag_ids))
        resp = {
            r.dag_id.replace('.', '__dot__'): {