[Bug][Go][Client] Downloaded File Does Not Exist When Returned to Caller

[icubbon]

Keep the file that gets written out to by the client->decode function

The calling code should be responsible for cleaning up the file returned from the Client. The file is already a tempFile so it is cleaned up by the OS eventually but can be cleaned up sooner.

Reverts #16303
Fixes #16953

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@wing328

[wing328]

cc @antihax (2017/11) @grokify (2018/07) @kemokemo (2018/09) @jirikuncar (2021/01) @ph4r5h4d (2021/04) @lwj5 (2023/04)

[wing328]

@icubbon thanks for the fix. can you please merge the latest master into your branch as I've just merged #16956 so that you can leverage the Echo API client to test this fix and get it covered moving forward?

Can you please add a test similar to https://github.com/OpenAPITools/openapi-generator/blob/master/samples/client/echo_api/python/test/test_manual.py#L110C29-L110C29?

To run the echo server locally, please refer to https://github.com/OpenAPITools/openapi-generator/wiki/Integration-Tests#echo-server

[icubbon]

@wing328 It looks like there is already a test that is being skipped that would catch this. I removed the t.Skip call and fixed the compilation errors in that package. The tests won't run unless go get github.com/stretchr/testify/assert is run to add testify to the go.mod file.

But that test now runs. I did confirm that it catches the problem and confirms that it is fixed.

openapi-generator/samples/client/echo_api/go/test/api_body_test.go

Line 25 in 4402635

t.Run("Test BodyAPIService TestBinaryGif", func(t *testing.T) {