feat(progress-bar): Missing `--mdc-linear-progress-active-indicator-shape` property for progress-bar

[uus-dev]

Feature Description

Currently if I want to change the shape of the progress bar to be round like, I only have the --mdc-linear-progress-track-shape to set the track shape, but not the same option for the shape of the active-indicator, which will still be square. Also, only setting the --mdc-linear-progress-track-shape, will result in the active indicator overflowing, leaving me with an inconsistent progress-bar (see 1st picture)

Hence that leaves me with the better option of just setting the border-radius of the mat-progress-bar element itself, because this doesn't cause the active-indicator to overflow. In this case the --mdc-linear-progress-track-shape becomes redundant.

1. Screenshot with --mdc-linear-progress-track-shape: 4px;, causing the active-indicator to overflow:

2. Screenshot with --mdc-linear-progress-track-shape: 4px; and border-radius: 4px, rendering the --mdc-linear-progress-track-shape redundant:

3. Screenshot with only border-radius: 4px; leaving me with an almost round progress bar, except that the active-indicator is not actually round.

So there need to be an option to set the --mdc-linear-progress-active-indicator-shape like for other components, so that the active-indicator can be made round, as shown in the Token and Specs section in the Material 3 specification

Use Case

This would enable a very relevant an normal use case that is also shown in the Token and Specs section in the Material 3 specification.