fix(otel): Avoid deadlock in SentryContextStorage.root() with virtual threads (#5234)

* fix(otel): Avoid deadlock in SentryContextStorage.root() with virtual threads

SentryContextStorage.root() called SentryContextWrapper.wrap() which
triggers scope.clone() and acquires locks. Under virtual threads,
ReentrantLock.unlock() can re-enter root() via OpenTelemetry executor
instrumentation on ForkJoinPool.execute(), causing a deadlock.

Return the default OTel root context without wrapping. Scopes are
resolved later via attach() or Sentry.getCurrentScopes().

Fixes GH-5226
Co-Authored-By: Claude <noreply@anthropic.com>

* changelog

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Co-authored-by: Claude <noreply@anthropic.com>