### Apache Airflow version

2.1.3 (latest released)

### Operating System

macOS Big Sur 11.3.1

### Versions of Apache Airflow Providers

n/a

### Deployment

Astronomer

### Deployment details

default Astronomer deployment with some test DAGs

### What happened

In the UI for DAGRuns there are checkboxes that allow multiple DAGRuns to be selected.

![image](https://user-images.githubusercontent.com/89415310/133841290-94cda771-9bb3-4677-8530-8c2861525719.png)

Within the Actions menu on this same view, there is a Delete option which allows multiple DAGRuns to be deleted at the same time.

![image](https://user-images.githubusercontent.com/89415310/133841362-3c7fc81d-a823-4f41-8b1d-64be425810ce.png)

Task instance view on the UI does not offer the same option, even though Task Instances can be individually deleted with the trash can button.

![image](https://user-images.githubusercontent.com/89415310/133841442-3fee0930-a6bb-4035-b172-1d10b85f3bf6.png)


### What you expected to happen

I expect that the Task Instances can also be bulk deleted, in the same way that DAGRuns can be.

### How to reproduce

Open up Task Instance and DAGRun views from the Browse tab and compare the options in the Actions dropdown menus.

### Anything else

_No response_

### Are you willing to submit PR?

- [X] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

airflow/www/views.py
"""Show Not Found on screen for any error in the Webserver"""
    return (
        render_template(
            'airflow/not_found.html',
            hostname=socket.getfqdn()
            if conf.getboolean('webserver', 'EXPOSE_HOSTNAME', fallback=True)
            else 'redact',
        ),
        404,
    )
def show_traceback(error):
    """Show Traceback for a given error"""
    return (
        render_template(
            'airflow/traceback.html',
            python_version=sys.version.split(" ")[0],
            airflow_version=version,
            hostname=socket.getfqdn()
            if conf.getboolean('webserver', 'EXPOSE_HOSTNAME', fallback=True)
            else 'redact',
            info=traceback.format_exc()
            if conf.getboolean('webserver', 'EXPOSE_STACKTRACE', fallback=True)
            else 'Error! Please contact server admin.',
        ),
        500,
    )
class AirflowBaseView(BaseView):