fix: add t.ksr to expected tracestate in OT compatibility tests

The _dd.p.ksr propagated tag also appears in W3C tracestate as t.ksr.
Update OT31 and OT33 test expectations for the UNSET context priority
case where the agent-rate sampler runs.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: bm1549

dd-trace-ot/src/ot31CompatibilityTest/groovy/OT31ApiTest.groovy

@@ -101,6 +101,7 @@ class OT31ApiTest extends DDSpecification {
     def effectiveSamplingMechanism = contextPriority == UNSET ? AGENT_RATE : samplingMechanism
     def expectedTracestate = "dd=s:${propagatedPriority};p:${DDSpanId.toHexStringPadded(spanId)}" +
       (propagatedPriority > 0 ? ";t.dm:-" + effectiveSamplingMechanism : "") +
+      (contextPriority == UNSET ? ";t.ksr:1" : "") +
       ";t.tid:${traceId.toHexStringPadded(32).substring(0, 16)}"
     def expectedTextMap = [
       "x-datadog-trace-id"         : context.toTraceId(),

dd-trace-ot/src/ot33CompatibilityTest/groovy/OT33ApiTest.groovy

@@ -90,6 +90,7 @@ class OT33ApiTest extends DDSpecification {
     def effectiveSamplingMechanism = contextPriority == UNSET ? AGENT_RATE : samplingMechanism
     def expectedTracestate = "dd=s:${propagatedPriority};p:${DDSpanId.toHexStringPadded(spanId)}" +
       (propagatedPriority > 0 ? ";t.dm:-" + effectiveSamplingMechanism : "") +
+      (contextPriority == UNSET ? ";t.ksr:1" : "") +
       ";t.tid:${traceId.toHexStringPadded(32).substring(0, 16)}"
     def expectedTextMap = [
       "x-datadog-trace-id"         : context.toTraceId(),