Tab title isn't hidden for session tabs after the tab threshold is reached

[srirambv]

Test plan

See #9512

Original issue description

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

• Describe the issue you encountered:
  Tab title isn't hidden for session tabs after the tab threshold is reached

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

• Brave Version (revision SHA):
  Brave 0.17.1
  rev 84dbc8e
  Muon 4.0.3

• Steps to reproduce:

  1. Pin 8-10 tabs on a clean install
  2. Open 20 tabs including a number of session tabs
  3. Tab title isn't hidden behind the session tab icon when the threshold size is reached

• Actual result:
  Tab title isn't hidden for session tabs after the tab threshold is reached

• Expected result:
  Should hide text behind session tab icon once the threshold is reached

• 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?
  No

• Can this issue be consistently reproduced?
  Yes

• Extra QA steps:
  1.
  2.
  3.

• Screenshot if needed:
  

• Any related issues: