Fixes dnd for bookmark toolbar

[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.
• Request a security/privacy review as needed. (Ask a Brave employee to help if you cannot access this document.)

Resolves #12481
Resolves #12506

Auditors:

Test Plan: defined in #12481 and #12506

Reviewer Checklist:

• Request a security/privacy review as needed if one was not already requested.

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

[codecov-io]

Codecov Report

Merging #12517 into master will decrease coverage by 0.02%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #12517      +/-   ##
==========================================
- Coverage   55.91%   55.89%   -0.03%     
==========================================
  Files         278      278              
  Lines       26983    26990       +7     
  Branches     4363     4365       +2     
==========================================
- Hits        15087    15085       -2     
- Misses      11896    11905       +9

Flag	Coverage Δ
#unittest	55.89% <100%> (-0.03%)	⬇️

Impacted Files	Coverage Δ
app/browser/reducers/bookmarksReducer.js	96.92% <100%> (ø)	⬆️
app/common/state/bookmarksState.js	99.11% <100%> (+0.01%)	⬆️
app/common/state/bookmarkFoldersState.js	100% <100%> (ø)	⬆️
app/browser/reducers/bookmarkFoldersReducer.js	100% <100%> (ø)	⬆️
js/stores/appStoreRenderer.js	91.17% <0%> (-8.83%)	⬇️
app/renderer/components/reduxComponent.js	84.37% <0%> (-6.25%)	⬇️
js/stores/windowStore.js	27.25% <0%> (-0.31%)	⬇️

[cezaraugusto]

master c296032
0.21.x 9202b0b
0.20.x 81346ee