dashboard: fix a bug that could not handle proxy requests correctly (#5326)

[ti-chi-bot]

This is an automated cherry-pick of #5326

What problem does this PR solve?

Issue Number: Close #5321

What is changed and how does it work?

Only process headers added by PD.

Check List

Tests

• Unit test

Related changes

• Need to cherry-pick to the release branch

Release note

Fix a bug that could not handle dashboard proxy requests correctly.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• bufferflies
• nolouch

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[codecov]

Codecov Report

Base: 75.45% // Head: 75.61% // Increases project coverage by +0.15% 🎉

Coverage data is based on head (ff7be6a) compared to base (4ab9c0e).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@               Coverage Diff               @@
##           release-6.1    #5345      +/-   ##
===============================================
+ Coverage        75.45%   75.61%   +0.15%     
===============================================
  Files              307      307              
  Lines            30387    30388       +1     
===============================================
+ Hits             22929    22978      +49     
+ Misses            5465     5432      -33     
+ Partials          1993     1978      -15     

Flag	Coverage Δ
unittests	75.61% <100.00%> (+0.15%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pkg/dashboard/adapter/redirector.go	91.30% <100.00%> (+6.85%)	⬆️
pkg/tempurl/tempurl.go	45.00% <0.00%> (-15.00%)	⬇️
server/storage/kv/etcd_kv.go	72.46% <0.00%> (-13.05%)	⬇️
server/region_syncer/server.go	82.06% <0.00%> (-5.44%)	⬇️
client/base_client.go	79.89% <0.00%> (-2.07%)	⬇️
tools/pd-ctl/pdctl/command/operator.go	66.66% <0.00%> (-1.15%)	⬇️
server/cluster/cluster.go	82.84% <0.00%> (-0.91%)	⬇️
server/server.go	72.81% <0.00%> (-0.84%)	⬇️
server/encryptionkm/key_manager.go	72.90% <0.00%> (-0.80%)	⬇️
server/config/persist_options.go	93.23% <0.00%> (-0.72%)	⬇️
... and 19 more

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[nolouch]

@HunDunDM plz check it, go mod tidy has some changes.

[bufferflies]

LGTM

[nolouch]

/merge

[ti-chi-bot]

@nolouch: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: a875a13

[bufferflies]

plz @HunDunDM , fix the unit test by remove assert.

[nolouch]

/merge

[ti-chi-bot]

@nolouch: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: ff7be6a