Added A/A testing

[karrtikr]

For #6793

• Pull request represents a single change (i.e. not fixing disparate/unrelated things in a single PR)
• Title summarizes what is changing
• Has a news entry file (remember to thank yourself!)
• Appropriate comments and documentation strings in the code
• Has sufficient logging.
• Has telemetry for enhancements.
• Unit tests & system/integration tests are added/updated
• [ ] Test plan is updated as appropriate
• [ ] package-lock.json has been regenerated by running npm install (if dependencies have changed)
• [ ] The wiki is updated with any design decisions/details.

[codecov-io]

Codecov Report

Merging #7173 into master will decrease coverage by 0.02%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #7173      +/-   ##
==========================================
- Coverage    58.5%   58.47%   -0.03%     
==========================================
  Files         485      486       +1     
  Lines       21446    21458      +12     
  Branches     3462     3462              
==========================================
+ Hits        12546    12547       +1     
- Misses       8122     8135      +13     
+ Partials      778      776       -2

Impacted Files	Coverage Δ
src/client/activation/serviceRegistry.ts	100% <100%> (ø)	⬆️
src/client/activation/aaTesting.ts	100% <100%> (ø)
src/client/common/experimentGroups.ts	100% <100%> (ø)	⬆️
src/client/common/logger.ts	68.55% <0%> (-6.92%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 83185a6...8bd0add. Read the comment docs.

[ericsnowcurrently]

LGTM