Fix session_transaction_spec to use CSOT for timeout test

The test expected TimeoutError from a non-CSOT with_transaction call.
Per the spec, non-CSOT mode re-raises the original error directly.
Add timeout_ms: 5000 to enable CSOT so the test matches its intent.

Author: comandeo-mongo

spec/mongo/session_transaction_spec.rb

@@ -136,7 +136,7 @@ class SessionTransactionSpecError < StandardError; end
         allow(session).to receive('check_transactions_supported!').and_return true
 
         expect do
-          session.with_transaction do
+          session.with_transaction(timeout_ms: 5000) do
             exc = Mongo::Error::OperationFailure.new('timeout test')
             exc.add_label('TransientTransactionError')
             raise exc