Onboarding: Connect to existing Ads account in Google Accounts Card

[ankitrox]

Changes proposed in this Pull Request:

Closes #2596 .

Replace this with a good description of your changes & reasoning.

Screenshots:

Detailed test instructions:

Additional details:

Changelog entry

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 63.0%. Comparing base (896c681) to head (4173593).

Additional details and impacted files

@@                             Coverage Diff                              @@
##           feature/2567-kickoff-mc-ads-account-creation   #2640   +/-   ##
============================================================================
  Coverage                                          63.0%   63.0%           
============================================================================
  Files                                               323     323           
  Lines                                              5160    5156    -4     
  Branches                                           1269    1265    -4     
============================================================================
- Hits                                               3250    3248    -2     
+ Misses                                             1734    1733    -1     
+ Partials                                            176     175    -1     

Flag	Coverage Δ
js-unit-tests	63.0% <ø> (+<0.1%)	⬆️

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see 3 files with indirect coverage changes