[PM-6195] Refactor injection of services in browser services module

[djsmith85]

Type of change

- [ ] Bug fix
- [ ] New feature development
- [X] Tech debt (refactoring, code cleanup, dependency upgrades, etc)
- [ ] Build/deploy pipeline (DevOps)
- [ ] Other

Objective

As part of the StateProvider work we are re-visiting the usage of shared services between the background and popup and removing all unnecessary services.

Code changes

• Remove PasswordStrengthService from popup/services.module - fc7d8b2
  • No state needs to be shared between background and popup. Meaning it can be safely removed.
• Remove ImportService from popup/services.module - fd87d37
  • Can be removed as the import.component is standalone and provides the importService. For the fileless LP import we also don't need the injector within the popup as it's provided via jslib.services.module.

Before you submit

• Please add unit tests where it makes sense to do so (encouraged but not required)
• If this change requires a documentation update - notify the documentation team
• If this change has particular deployment requirements - notify the DevOps team
• Ensure that all UI additions follow WCAG AA requirements

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 26.28%. Comparing base (7240285) to head (fd87d37).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #8405   +/-   ##
=======================================
  Coverage   26.28%   26.28%           
=======================================
  Files        2281     2281           
  Lines       66847    66845    -2     
  Branches    12566    12566           
=======================================
  Hits        17571    17571           
+ Misses      47907    47905    -2     
  Partials     1369     1369           

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