docs: edit air gapped docs to clean up envoy proxy customizations

[arkodg]

Fixes: #6570

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.98%. Comparing base (c3abe4e) to head (0b82524).
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6577      +/-   ##
==========================================
+ Coverage   70.86%   70.98%   +0.11%     
==========================================
  Files         224      225       +1     
  Lines       38733    38919     +186     
==========================================
+ Hits        27447    27625     +178     
+ Misses       9697     9693       -4     
- Partials     1589     1601      +12     

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[zirain]

/retest

[arkodg]

The docs-lint error doesn't seem related to this PR