Add clear all button in notifications

[CarolineDenis]

Fixes #3890

[maxpatiiuk]

few things in addition to what Jason mentioned

[melton-jason]

Code looks good now!

[carlosmbe]

Can we put somewhere more easily noticeable. Like parallel the close button or on top. Otherwise, it's a bit hard to notice.

[carlosmbe]

If there's only one notification. We shouldn't have the button. Otherwise, it seems great.

Edit:

There seems to be lingering notification that only leaves after opening up the notifications overlay

Screen.Recording.2023-08-25.at.4.26.32.PM.mp4

[bronwyncombs]

• Could we make it less wide and add this to the bottom left of the dialog, in-line with the Close button?
• It should be tied to button color preferences, maybe as a "Secondary"?
• Do we think it's consistent to keep this as a button that's highlighted when scrolled over?
• Could we also remove the slight border on the top?

Screen.Recording.2023-09-27.at.9.27.25.AM.mov