Fixes removal of bookmarkLocation cache when removing bookmark folder

[NejcZdovc]

Submitter Checklist:

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).
• Tagged reviewers and labelled the pull request as needed.

Resolves #10908

Auditors:

Test Plan:

• import bookmark file 300 from qa repo
• delete folder 100-199
• check that state was cleaned correctly (state->cache->bookmarkLocation should only have 99 items inside)

Reviewer Checklist:

Tests

• Adequate test coverage exists to prevent regressions
• Tests should be independent and work correctly when run individually or as a suite ref
• New files have MPL2 license header

[NejcZdovc]

unit tests will be added in #10310

[codecov-io]

Codecov Report

Merging #10909 into master will decrease coverage by <.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master   #10909      +/-   ##
==========================================
- Coverage   54.14%   54.14%   -0.01%     
==========================================
  Files         248      248              
  Lines       21750    21751       +1     
  Branches     3383     3383              
==========================================
  Hits        11777    11777              
- Misses       9973     9974       +1

Flag	Coverage Δ
#unittest	54.14% <0%> (-0.01%)	⬇️

Impacted Files	Coverage Δ
app/common/state/bookmarksState.js	76.33% <0%> (-0.35%)	⬇️

[ayumi]

tested and works!