docs: added JSONPatch example for modifying Bootstrap config using the EnvoyProxy resource

[alrai]

What type of PR is this?

What this PR does / why we need it:
Enhances the existing docs.

Which issue(s) this PR fixes:
Fixes #4742

Release Notes: No

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 65.60%. Comparing base (71c0b54) to head (4923e58).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4772      +/-   ##
==========================================
- Coverage   65.61%   65.60%   -0.02%     
==========================================
  Files         211      211              
  Lines       31961    31961              
==========================================
- Hits        20972    20968       -4     
- Misses       9750     9753       +3     
- Partials     1239     1240       +1     

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[alrai]

@zhaohuabing In this PR I modified the 3 files including the one you mentioned:

site/content/en/docs/tasks/operations/customize-envoyproxy.md
site/content/en/latest/tasks/operations/customize-envoyproxy.md
site/content/en/v1.2/tasks/operations/customize-envoyproxy.md

[zhaohuabing]

@zhaohuabing In this PR I modified the 3 files including the one you mentioned:
Sorry that I missed that. LGTM thanks!