client/http: use KeyRange to differentiate the encoding format of the key

[JmPotato]

What problem does this PR solve?

Issue Number: ref #7300.

What is changed and how does it work?

Use `KeyRange` to differentiate the encoding format of the key.

Check List

Tests

• Unit test
• Integration test

Release note

None.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• HuSharp
• rleungx

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[codecov]

Codecov Report

Merging #7449 (fdeda3f) into master (58e9b20) will decrease coverage by 0.08%.
The diff coverage is 52.63%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7449      +/-   ##
==========================================
- Coverage   74.25%   74.17%   -0.08%     
==========================================
  Files         451      451              
  Lines       49587    49593       +6     
==========================================
- Hits        36820    36787      -33     
- Misses       9470     9504      +34     
- Partials     3297     3302       +5     

Flag	Coverage Δ
unittests	74.17% <52.63%> (-0.08%)	⬇️

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[JmPotato]

/merge

[ti-chi-bot]

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[ti-chi-bot]

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

Commit hash: fdeda3f