Delete symmetry information from fcidump to avoid PySCF error

[kevinsung]

Without this change, PySCF throws an error if you try to run a calculation. Example:

from pyscf import mcscf, tools

# Specify molecule properties
num_orbitals = 16
num_elec_a = num_elec_b = 5
open_shell = False
spin_sq = 0

# Read in molecule from disk
mf_as = tools.fcidump.to_scf("../molecules/n2_fci.txt")

# Run FCI
cas = mcscf.CASCI(mf_as.run(), ncas=num_orbitals, nelecas=(num_elec_a, num_elec_b))
_, _, fci_vec, _, _ = cas.kernel()

Traceback (most recent call last):
  File "/home/kevinsung/projects/qiskit-addon-sqd/docs/tutorials/repro.py", line 15, in <module>
    _, _, fci_vec, _, _ = cas.kernel()
                          ^^^^^^^^^^^^
  File "/home/kevinsung/.pyenv/versions/tutorials/lib/python3.11/site-packages/pyscf/mcscf/casci_symm.py", line 59, in
 kernel
    mo_coeff = self.mo_coeff = label_symmetry_(self, mo_coeff, ci0)
                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/kevinsung/.pyenv/versions/tutorials/lib/python3.11/site-packages/pyscf/mcscf/casci_symm.py", line 128, i
n label_symmetry_
    ' '.join([symm.irrep_id2name(mc.mol.groupname, irrep)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/kevinsung/.pyenv/versions/tutorials/lib/python3.11/site-packages/pyscf/mcscf/casci_symm.py", line 128, i
n <listcomp>
    ' '.join([symm.irrep_id2name(mc.mol.groupname, irrep)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/kevinsung/.pyenv/versions/tutorials/lib/python3.11/site-packages/pyscf/symm/addons.py", line 502, in irr
ep_id2name
    return param.CHARACTER_TABLE[gpname][irrep_id_in_d2h][0]
           ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^
KeyError: 'N/a'