Stacked progress bars don't use transitions when updated

[mfosterw]

Prerequisites

• I have searched for duplicate or closed issues
• I have validated any HTML to avoid common problems
• I have read the contributing guidelines

Describe the issue

Stacked progress bars using the new ".progress-stack" class change their width instantly when updated with Javascript rather than using a transition like they did (and still do) with the old style. This produces an undesirable visual effect when changing the width by more than a minuscule amount.

Reduced test cases

https://stackblitz.com/edit/bootstrap-5-qckpcxzb?file=src%2Findex.html

What operating system(s) are you seeing the problem on?

macOS

What browser(s) are you seeing the problem on?

Firefox

What version of Bootstrap are you using?

5.3.7