Convert helpfulText with Aphrodite

[luixxiul]

Closes #10608

Auditors:

Test Plan:

1. Open about:preferences#extensions
2. Make sure the help text is rendered

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.

Test Plan:

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

[codecov-io]

Codecov Report

Merging #10609 into master will increase coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #10609      +/-   ##
==========================================
+ Coverage   54.19%    54.2%   +0.01%     
==========================================
  Files         244      244              
  Lines       21109    21114       +5     
  Branches     3258     3258              
==========================================
+ Hits        11440    11445       +5     
  Misses       9669     9669

Flag	Coverage Δ
#unittest	54.2% <100%> (+0.01%)	⬆️

Impacted Files	Coverage Δ
...p/renderer/components/preferences/extensionsTab.js	89.65% <ø> (ø)	⬆️
app/renderer/components/preferences/helpfulText.js	100% <100%> (ø)	⬆️

[cezaraugusto]

++