Update pulse gate tutorial for changes in fake backends

In Qiskit/qiskit#8665 very large pulse properties for long retired
20q backends are removed to save disk space and reduce overhead. However
the pulse gates tutorial was still relying on these fake backends having
pulse properties. This commit updates the tutorial to use a different
backend to unblock that PR. Additionally, the deprecate import
statements used in the tutorial are updated to avoid the deprecation
warning.