[parametric] [Python] Assert that the default context propagation only extracts/injects Datadog headers

[ZStriker19]

Description

Enable header precedence test for python tracer, to be merged once https://github.com/DataDog/dd-trace-py/pull/6256 is merged into tracer.

Motivation

Reviewer checklist

• [ ] If this PR modifies anything else than strictly the default scenario, then add the run-all-scenarios label (more info).
• [ ] CI is green
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[ZStriker19]

closed because we're reassessing if we want to make this change.