DSC: `sample_rate` is not set when sample decision is forced

[Lms24]

Problem Statement

When starting a transaction, users can force a sample decision by settingtransaction.sampled to true or false. We don't set the sample rate in the transaction metadata in this case:

sentry-javascript/packages/tracing/src/hubextensions.ts

Lines 55 to 64 in 70883aa

	// if the user has forced a sampling decision by passing a `sampled` value in their transaction context, go with that
	if (transaction.sampled !== undefined) {
	transaction.setMetadata({
	transactionSampling: { method: 'explicitly_set' },
	});
	return transaction;
	}
	// we would have bailed already if neither `tracesSampler` nor `tracesSampleRate` were defined, so one of these should
	// work; prefer the hook if so