Revert default import of rzx_templates

This was made in order to simplify some import paths, but as a side
effect it caused ten `QuantumCircuit`s to be created on import of
`qiskit`, which spoiled the QPY backwards compatibility tests and likely
had import performance implications.

The import of this likely should not need to create circuits, but for
now, we revert its import rather than making a change this close to
release.

qiskit/transpiler/passes/calibration/__init__.py

@@ -13,4 +13,3 @@
 """Module containing transpiler calibration passes."""
 
 from .builders import RZXCalibrationBuilder, RZXCalibrationBuilderNoEcho, PulseGates
-from .rzx_templates import rzx_templates

releasenotes/notes/0.19/add-pulse-gate-pass-dc347177ed541bcc.yaml

@@ -82,11 +82,11 @@ deprecations:
     are deprecated, and will be removed in a future release.
     The import path::
 
-        from qiskit.transpiler.passes.scheduling.rzx_templates.rzx_templates import rzx_templates
+        from qiskit.transpiler.passes.scheduling.rzx_templates import rzx_templates
 
     is also deprecated, and will be removed in a future release.
     You should use the new import paths::
 
         from qiskit.transpiler.passes import RZXCalibrationBuilder
         from qiskit.transpiler.passes import RZXCalibrationBuilderNoEcho
-        from qiskit.transpiler.passes.calibration import rzx_templates
+        from qiskit.transpiler.passes.calibration.rzx_templates import rzx_templates