fix: read http entity only once in integ test

[zhichao-aws]

Description

In main and 2.x we use different http dependency in integ test. In main the dependency is from org.apache.hc.core5.http, and in 2.x it's from org.apache.http.
Current integ test code in main works well, but in 2.x, we can not read a http entity twice. The entity is a stream, if read twice, the result is null. We can solve this by cache the result and read it only once 28bfc01.
Although in main it works well, we can also modify this to keep it consistent between main and 2.x. If we modify some code in the future, this issue will not be a blocker for auto backport.

Issues Resolved

[List any issues this PR will resolve]

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff

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[zhichao-aws]

No need to backport, the fix is already in 2.x

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (34ae75f) 81.29% compared to head (dc384ba) 81.29%.

Additional details and impacted files

@@            Coverage Diff            @@
##               main      #94   +/-   ##
=========================================
  Coverage     81.29%   81.29%           
  Complexity      152      152           
=========================================
  Files            12       12           
  Lines           882      882           
  Branches        115      115           
=========================================
  Hits            717      717           
  Misses          106      106           
  Partials         59       59           

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