Increase Padding on Pinned Tabs

[jonathansampson]

Test plan

#10533 (comment)

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• Did you search for similar issues before submitting this one?
  Yes

• Describe the issue you encountered:
  Pinned tabs would benefit from better UI/UX with greater lateral padding. See this tweet by a Brave user.

If this request is implemented, we should probably consider the UI/UX of narrow tabs in general. A cursory glance at the current implementation reveals that pinned tabs, and standard narrow tabs, are displayed differently.

• Platform (Win7, 8, 10? macOS? Linux distro?):
  Desktop

• Brave Version (revision SHA):
  N/A

• Steps to reproduce:

  1. Create a pinned tab

• Actual result:
  Padding is tight, at 2px.

• Expected result:
  More lateral padding (perhaps 5px?)

• Will the steps above reproduce in a fresh profile? If not what other info can be added?
  Yes

• Is this an issue in the currently released version?
  Yes

• Can this issue be consistently reproduced?
  Yes

• Screenshot if needed:
  (Top: Safari, Bottom: Brave)
  

[cezaraugusto]

+1

[NejcZdovc]

On design call we decided to increase it from 2 to 4px