DAG Gantt chart taskgroup toggle

### Description

# Description
In the Gantt chart view of a DAG. TaskGroups are displayed on the chart like TIs are. This is potential visual clutter, since TaskGroups show their gantt duration as the envelope of the tasks inside it. This makes the gantt chart difficult to interpret, since it makes it possible that some lines on the chart are "very long" even though the actual time TIs spent running might be negligible.

# Proposed solution
Add a toggle button in the gannt chart display to hide the running time of taskgroups. Since taskgroups also act to organize TIs in the gantt chart, this toggle would not hide task groups in the sidebar, only to stop their runtimes from rendering in the chart.

### Use case/motivation

I want to use the gantt chart view to see which tasks take how long at a glance. I considered getting rid of TaskGroups in my dags to aleviate this gantt chart issue, but I found that TaskGroups are too useful when logically organizing a DAG to forego for occasional inspection of runtimes.

### Related issues

_No response_

### Are you willing to submit a PR?

- [ ] 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)