### 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
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):