fixing issue with empty block

Author: weinbe58

src/bloqade/qasm2/rewrite/insert_qubits.py

@@ -19,6 +19,7 @@ def rewrite_Statement(self, node: ir.Statement) -> rewrite_abc.RewriteResult:
         n_qubits_stmt.detach()
         node.detach()
         if block.first_stmt is None:
+            block.stmts.append(n_qubits_stmt)
             block.stmts.append(node)
         else:
             node.insert_before(block.first_stmt)