[BUG] Consecutive unrolls fail with `consolidate_qubits=True`

[TheGupta2012]

Environment

• PyQASM version: 1.0.1
• Python version: 3.12
• Operating system: macOS

What happened?

In [8]: from pyqasm import loads
   ...: 
   ...: qasm3_string = """OPENQASM 3.0;
   ...: include "stdgates.inc";
   ...: qubit[2] q;
   ...: qreg q2[3];
   ...: barrier q2;
   ...: barrier q, q2;
   ...: """
   ...: mod = loads(qasm3_string)
   ...: mod.unroll(consolidate_qubits = True)
   ...: mod.unroll(consolidate_qubits = True) 

raises -

ValidationError: Missing qubit register declaration for '__PYQASM_QUBITS__[2:]' in QuantumBarrier

Suggestions (Optional)

Looks like a bug in the handling of __PYQASM_QUBITS__ keyword in the qasm