Fix signer receiving a drained body on retries

[aouji]

Description

When retrying, the body can be drained, and there is already code that resets the request body on retries. The issue was that we were sending the drained request to the signer before reseting the request body, so signature would be based on an empty body

Issues Resolved

#202

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.99%. Comparing base (06a6dc8) to head (62ff49c).
Report is 70 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #620       +/-   ##
===========================================
+ Coverage   57.29%   67.99%   +10.70%     
===========================================
  Files         315      376       +61     
  Lines        9823     8862      -961     
===========================================
+ Hits         5628     6026      +398     
+ Misses       2902     1555     -1347     
+ Partials     1293     1281       -12     

Flag	Coverage Δ
integration	60.35% <0.00%> (+9.51%)	⬆️
unit	15.37% <100.00%> (+2.53%)	⬆️

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

Files with missing lines	Coverage Δ
opensearchtransport/opensearchtransport.go	87.16% <100.00%> (+2.00%)	⬆️

... and 273 files with indirect coverage changes

[aouji]

I'm not sure why integration tests are failing. Doesn't seem related to my change.

BTW sorry for the mess I seem to have created in this PR. I can't re-trigger DCO and code coverage checks. Please trigger on your side or let me know if I need to close this and open a new PR

[dblock]

Thank you for fixing this! Let's deal with the integ test separately.

--- FAIL: TestNodes (1.48s)
    --- FAIL: TestNodes/Stats (0.06s)
        --- FAIL: TestNodes/Stats/without_request (0.05s)

You will need to fix DCO, git commit --amend -s and force push your branch please?

[aouji]

DCO is now fixed

[dblock]

Any ideas why the integ test started failing?

=== RUN   TestNodes/Stats/without_request
    api_nodes_test.go:182: 
        	Error Trace:	/home/runner/work/opensearch-go/opensearch-go/internal/test/helper.go:147
        	            				/home/runner/work/opensearch-go/opensearch-go/opensearchapi/api_nodes_test.go:182
        	Error:      	Should be empty, but was [{"op":"remove","path":"/nodes/tFKzdl01Ss2oOLoYJtcXcg/indices/search/request/took"}]
        	Test:       	TestNodes/Stats/without_request

[Jakob3xD]

Any ideas why the integ test started failing?

=== RUN   TestNodes/Stats/without_request
    api_nodes_test.go:182: 
        	Error Trace:	/home/runner/work/opensearch-go/opensearch-go/internal/test/helper.go:147
        	            				/home/runner/work/opensearch-go/opensearch-go/opensearchapi/api_nodes_test.go:182
        	Error:      	Should be empty, but was [{"op":"remove","path":"/nodes/tFKzdl01Ss2oOLoYJtcXcg/indices/search/request/took"}]
        	Test:       	TestNodes/Stats/without_request

The Integration tests runs against latest which was updated 7 days ago to 2.17. I assume the version adds the new field which is currently not present in our spec. We need to add it. Also fails in the dependency updates.

[dblock]

@Jakob3xD thanks for taking care of the integ tests in #623

@aouji rebase?