fix: disable -shadow host suffix append

[shreealt]

What type of PR is this?

bugfix

What this PR does / why we need it:
The current HTTPRoute Request Mirroring automatically appends a “-shadow” to the mirror requests Host header. According to the Envoy doc, this is used for logging.

However, this can be surprising to users, as the Host header is modified without explicit notice. It may also cause issues for application that depends on the original Host header.
Which issue(s) this PR fixes:

Fixes #7227

Release Notes: Yes/No

[shreealt]

I am kinda confused on how to write test cases for this one. Specially the part on how to confirm that the host header in mirrored HTTP message does not contain the shadow suffix.

I am reading existing test cases, however I would appreciate any help on this.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.14%. Comparing base (70af785) to head (77e3df6).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7229      +/-   ##
==========================================
+ Coverage   71.07%   71.14%   +0.07%     
==========================================
  Files         228      228              
  Lines       40825    40827       +2     
==========================================
+ Hits        29015    29048      +33     
+ Misses      10104    10079      -25     
+ Partials     1706     1700       -6     

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[zhaohuabing]

@shreealt thanks for picking this up!

Iet's hold off on this PR for now until a decision is made on how to address #7227.

[zhaohuabing]

@shreealt we discussed this in today's meeting. The decision is to make a breaking change to remove the -shadow suffix at this PR.

Feel free to proceed.

[zhaohuabing]

Nit: can we add a line of comment to explain why setting this option?

[zhaohuabing]

I am kinda confused on how to write test cases for this one. Specially the part on how to confirm that the host header in mirrored HTTP message does not contain the shadow suffix.

I am reading existing test cases, however I would appreciate any help on this.

RequestMirror is in a Gateway API feature, so we rely on the gateway api conformance test to verify it in the e2e tests.

For this PR, it's fine to verify it in the xds translator tests.

[zhaohuabing]

Could you add a note to the "breaking changes" section of the release-notes/current.yaml file?

[jukie]

/retest

[zhaohuabing]

LGTM. Thanks!