fix(docs): remove superfluous detail from quickstart

[krancour]

This is leftover from when the quickstart used to borrow a secret from Argo CD.

The quickstart no longer demonstrates that behavior, so the field removed by this PR was a useless detail and a distraction.

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (531a42d) 45.59% compared to head (cec93dd) 45.59%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1374   +/-   ##
=======================================
  Coverage   45.59%   45.59%           
=======================================
  Files         135      135           
  Lines       11664    11664           
=======================================
  Hits         5318     5318           
  Misses       6155     6155           
  Partials      191      191           

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