Check whether an IBM Quantum backend is reachable
Source:R/quantum_ibmq.R
quantum_ibmq_available.RdReturns TRUE when (i) reticulate is installed; (ii) the
qiskit_ibm_runtime Python module is importable; and (iii) the
IBMQ_TOKEN environment variable is set. The function does not
contact the network; it is a cheap preflight probe safe to call
from examples, tests and CI.