Add new LEDGER_NO_DELAY flag to help make QA easier

[bsclifton]

Fixes #12249

Auditors: @srirambv, @mrose17

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:

1. Launch Brave from command line with LEDGER_NO_DELAY=true and LEDGER_VERBOSE=true
2. Observe that the run method runs every 5 seconds. You should see a message like:

ledger client run: clientP=true delayTime=526163 LEDGER_NO_DELAY=true
          publisher  blockedP   stickyP  verified  excluded eligibleP  visibleP  contribP  duration    visits
+++ busyP=false

3. Quit Brave
4. Launch without LEDGER_NO_DELAY=true
5. Verify it does not run the method every 5 seconds

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 #12251 into master will decrease coverage by 0.05%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master   #12251      +/-   ##
==========================================
- Coverage    55.3%   55.24%   -0.06%     
==========================================
  Files         276      276              
  Lines       26647    26659      +12     
  Branches     4294     4297       +3     
==========================================
- Hits        14738    14729       -9     
- Misses      11909    11930      +21

Flag	Coverage Δ
#unittest	55.24% <0%> (-0.06%)	⬇️

Impacted Files	Coverage Δ
app/browser/api/ledger.js	50.59% <0%> (-0.32%)	⬇️
js/stores/appStoreRenderer.js	91.17% <0%> (-8.83%)	⬇️
app/renderer/components/reduxComponent.js	84.37% <0%> (-6.25%)	⬇️
js/stores/windowStore.js	26.71% <0%> (-0.3%)	⬇️

[srirambv]

++ Manual test plan works

[NejcZdovc]

code looks good to me

[bsclifton]

master 94a24e3
0.21.x ebed33b
0.20.x 596ba0d
0.19.x 15d618e