[Go] [Client] Don't Explode Query Params

[icubbon]

Query params were incorrectly being exploded all the time, regardless of the setting in the spec.
This was introduced with https://github.com/OpenAPITools/openapi-generator/pull/13909/files and addresses #14089

I think there are a lot of different ways to fix this issue, but this was a minimal way to get a slice of query params to be comma separated.

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@antihax @grokify @kemokemo @jirikuncar @ph4r5h4d @wing328

[wing328]

@icubbon thanks for the PR. Can you please PM me when you've time for a few quick questions on this PR?

https://join.slack.com/t/openapi-generator/shared_invite/zt-12jxxd7p2-XUeQM~4pzsU9x~eGLQqX2g