Add integration test for `DatadogTracing Off` in a child `<Location>` scope

[pawelchcki]

Context

PR #62 ("Respect child-scope override for tracing directives") fixed two bugs with identical shape: DatadogTracing Off and DatadogTrustInboundSpan Off were silently ignored when set inside a <Location> (the parent's implicit default true OR'd with the child's explicit false stayed true).

The existing integration test test_trust_inbound_span_directive (test/integration-test/scenarios/test_configuration.py:200) exercises DatadogTrustInboundSpan Off in a child <Location> (test/integration-test/scenarios/conf/directives.conf:39-43) and would catch a regression of that specific bug.

However, there is no analogous test for DatadogTracing Off in a child scope — which was the original motivating case per the PR description.

Proposal

Add a small integration test scenario that:

1. Defines a <Location> (e.g. /tracing-off) with DatadogTracing Off while the enclosing server scope leaves tracing at its default (on).
2. Issues a request to that location.
3. Asserts the agent receives no trace for it (while a control request to a sibling location still produces a trace, to guard against the test accidentally passing because tracing is globally off).

This mirrors the shape of test_trust_inbound_span_directive and closes the remaining coverage gap from #62.

References

• PR: Respect child-scope override for tracing directives #62
• Related test: test/integration-test/scenarios/test_configuration.py:200
• Related config: test/integration-test/scenarios/conf/directives.conf

[xlamorlette-datadog]

If possible, please also add a test for tracing_enabled: https://github.com/DataDog/httpd-datadog/pull/62/changes#r3118273325.