Handle unitary width issue in matplotlib drawer (#2849)
Handle unitary width issue in matplotlib drawer (#2849)

This commit handles fixes a spacing issue when drawing a unitary gate
with the matplotlib circuit drawer backend. Previously it was assuming
the gate was as wide as the operation name which was "unitary" and was
spacing based on that. However the gate is drawn with the name "u" and
is using a standard wide gate box (which has a layer width of 2). This
commit fixes the issue by treating the unitary gate as a standard wide
gate.

Fixes #2686
QISKit/qiskit-sdk-py,QISKit/qiskit-sdk-py,QISKit/qiskit-sdk-py