`tab.showCloseButton: hover|never` + `tabWidthMode: titleLength` should have some padding on the left of the tab

* [ ] There should be a bit more space to the right of the tab title to match the left side (next to icon)

Fixed in 1.16

### From 1.16.2142.0 bash on Aug 2nd

* [x] Gap between inactive tabs and content
- This might be related to the gap I was seeing in 2.8. Maybe fixing this (or at least understanding the root cause) might alleviate that issue as well.
- Tracked upstream at: https://github.com/microsoft/microsoft-ui-xaml/issues/7674
* [x] A light tabRow.BG in dark mode causes the chevron to be white:
* fixed in #13871
* [x] We need to remove `useMica`
* [x] With "tab.background" set to "terminalBackground":
* [x] Hover over a terminal tab -> the tab color doesn't change/give any visual feedback that it is being hovered over
* [x] Hover over a settings tab -> the tab color does change/give visual feedback

### additional

* [x] With `"tab.showCloseButton"` set to `"hover"`: Height of inactive tabs change upon hover - (can't seem to post a GIF in OneNote so try it yourself)
* Mike couldn't repro this, so maybe someone else can?

Reproduce the issue with `tab.showCloseButton` set to `hover` or `never` and `tabWidthMode` set to `titleLength`, then inspect the tab layout involved in Windows Terminal. Compare the left and right spacing around the tab title, and consider the work done when the right-side padding visually matches the left side without regressing close-button behavior.

Written by the indexing model from the issue text.