docs: Add notes to params from configmap examples to reduce user errors

[terrytangyuan]

These changes would reduce user errors:

1. Created ConfigMap in a different namespace
2. Required ConfigMap is not created before submitting the workflow
3. Required label in ConfigMap is missing.

Signed-off-by: Yuan Tang terrytangyuan@gmail.com

Tips:

• Maybe add you organization to USERS.md.
• Your PR needs to pass the required checks before it can be approved. If the check is not required (e.g. E2E tests) it does not need to pass
• Sign-off your commits to pass the DCO check: git commit --signoff.
• Run make pre-commit -B to fix codegen or lint problems.
• Say how how you tested your changes. If you changed the UI, attach screenshots.
• If changes were requested, and you've made them, then dismis the review to get it looked at again.
• You can ask for help!

[codecov]

Codecov Report

Merging #6894 (4cd7a34) into master (ef6aad6) will increase coverage by 0.00%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #6894   +/-   ##
=======================================
  Coverage   48.49%   48.50%           
=======================================
  Files         265      265           
  Lines       19258    19258           
=======================================
+ Hits         9340     9341    +1     
+ Misses       8865     8864    -1     
  Partials     1053     1053           

Impacted Files	Coverage Δ
workflow/controller/operator.go	71.11% <0.00%> (-0.10%)	⬇️
cmd/argo/commands/get.go	59.76% <0.00%> (+0.87%)	⬆️

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