"Show open tabs" button seems not to follow art guidelines

### What Happened?

I feel that the icon is not following the same style as, for example, home button, back and forward, or refresh. Even when you click on it, the color overlay is not a circle is an oval (I think because the current icon has different dimensions too).


### Steps to Reproduce

1. Launch Web.

### Expected Behavior

All icons should present the same visual style.

### OS Version

8.x (Early Access)

### Software Version

Latest release (I have run all updates)

### Log Output

_No response_

### Hardware Info

_No response_