Propagated context is discarded for random trace-ids

[cleverchuk]

Describe the bug
Pr #8012 drops propagated context when random trace id generator is used.

Steps to reproduce
added a test that fails without the fix.

What did you expect to see?
I expected access to data extracted by a propagator in the sampler#shouldSample when it's added to the context.

What did you see instead?
Null value for propagated keys.

What version and what artifacts are you using?
Artifacts: opentelemetry-sdk
Version: v1.60.1

Environment
Compiler: Corretto-25.0.2.10.1
OS: Darwin 24.6.0
Runtime (if different from JDK above): (e.g., "Oracle JRE 8u251")
OS (if different from OS compiled on): (e.g., "Windows Server 2019")

Additional context
Add any other context about the problem here.

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