OTEL: preserve span.kind if set as attributes in the builder

[amarziali]

What Does This Do

Some opentelemetry API versions don't allow setting the span kind on the builder (i.e. using setSpanKind method)

So things like

tracer.spanBuilder("..").setAttribute("span.kind", "client").start();

will have the span created with an internal span kind. However, if setAttribute is called after the span is started, the span.kind is overridden.

This might lead to inconsistencies and we should not set it to internal if set by setAttribute

Motivation

Additional Notes

Contributor Checklist

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Jira ticket: [PROJ-IDENT]

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[mcculls]

Looks reasonable

[PerfectSlayer]

Could you make sure the RFC gets updated it gets tested in system tests first?

[amarziali]

It's on hold since the behaviour related to how to handle properly span.kind is clarified