fix: move header to separate file

[AAfghahi]

SUMMARY

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TESTING INSTRUCTIONS

ADDITIONAL INFORMATION

• Has associated issue:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[codecov-commenter]

Codecov Report

❗ No coverage uploaded for pull request base (ch16648_headerSteps@eb53d28). Click here to learn what that means.
The diff coverage is n/a.

@@                  Coverage Diff                   @@
##             ch16648_headerSteps     #107   +/-   ##
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  Coverage                       ?   77.50%           
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  Files                          ?      966           
  Lines                          ?    49644           
  Branches                       ?     6304           
======================================================
  Hits                           ?    38478           
  Misses                         ?    10963           
  Partials                       ?      203           

Flag	Coverage Δ
javascript	72.28% <0.00%> (?)

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