ComposableAnnotatingSampler missing toString shows Object hash in composed description

[thswlsqls]

Describe the bug
ComposableAnnotatingSampler does not override toString(), so when another sampler nests it, the composed getDescription() output shows an Object hash instead of the annotating sampler's description.

Steps to reproduce

ComposableSampler.parentThreshold(
        ComposableSampler.annotating(ComposableSampler.alwaysOn(), Attributes.empty()))
    .getDescription();

What did you expect to see?

ComposableParentThresholdSampler{rootSampler=ComposableAnnotatingSampler{ComposableAlwaysOnSampler,{}}}

The other six ComposableSampler implementations all override toString() to return getDescription().

What did you see instead?

ComposableParentThresholdSampler{rootSampler=ComposableAnnotatingSampler@1a2b3c}

ComposableParentThresholdSampler builds its description by concatenating the nested sampler (ComposableParentThresholdSampler.java line 28), which calls toString() on the root sampler. ComposableAnnotatingSampler is the only implementation without that override, so it falls back to Object.toString().

What version and what artifacts are you using?
Artifacts: opentelemetry-sdk-extension-incubator
Version: main @ 09d6c17
How did you reference these artifacts? N/A

Environment
Compiler: Temurin 21
OS: N/A

Additional context
N/A