Reply to Comment in Pull request : Missing descriptive labels for buttons in the toolbar section

Issue Summary

In the toolbar available for the reply comment input field, the toolbar buttons have missing descriptive labels.

Tested URL

https://instenv-17510-hwan.instenv.internal.atlassian.com/projects/T1/repos/test1.1/pull-requests/3/overview

Steps to Reproduce

1. Launch the URL
2. Navigate to the comments section in the main content area
3. Activate the "Reply" link under any comment and navigate into the text input area.

Screenshot

Actual Results

The buttons in the toolbar for the Reply input in the comment section for pull requests have some missing descriptive labels for the buttons. The buttons in the toolbar such as "Bold", "Italic" etc have no label present, although they have an aria-label associated with them. In the absence of unique and descriptive labels, it becomes difficult for screen reader users to understand the purpose of the form control. If the purpose of the form control is not clear, users will find it difficult to interact with the control. 

Expected Results

Provide an appropriate label or title such as "Bold", or "Italic" for the button. Label or title is helpful for users with visual disabilities, learning disabilities, users browsing with text browsers etc. to understand the information conveyed using buttons. 

Workaround

Currently, there is no known workaround for this behaviour. A workaround will be added here when available.

Bug Ref: 735841