Remove qiskit aer translation stage

This commit removes the qiskit aer translation plugin. This was added as
a workaround for a Qiskit/qiskit#11351. This has been fixed in Qiskit
since 0.45.2 and is no longer necessary. The mechanism by which the
workaround worked was unsound in practice as it was mutating the target
and also explicitly using private attributes of the Target. This is
causing real issues now as it only worked by assuming the target wasn't
shared between passmanagers which is never guaranteed. Similarly the
reliance on internal private attributes of the Target class will cause
issues in the future when the target internals change (see
Qiskit/qiskit#12292). This commit opts to remove the plugin in its
entirity as it's no longer necessary and actively causing issues with
Qiskit 1.1 and transpiling targeting aer backends with >1 circuit. As
it's private internal detail there isn't a release note.

Fixes Qiskit/qiskit#12425
Fixes Qiskit#2141

qiskit_aer/backends/aerbackend.py

@@ -737,10 +737,3 @@ def __repr__(self):
         name = self.__class__.__name__
         display = f"'{self.name}'"
         return f"{name}({display})"
-
-    def get_translation_stage_plugin(self):
-        """use custom translation method to avoid gate exchange"""
-        if self._target is None:
-            return "aer_backend_plugin"
-        else:
-            return None

setup.py

@@ -22,7 +22,7 @@
 extras_requirements = {"dask": ["dask", "distributed"]}
 
 requirements = [
-    "qiskit>=0.45.0",
+    "qiskit>=0.45.2",
     "numpy>=1.16.3",
     "scipy>=1.0",
     "psutil>=5",
@@ -114,9 +114,4 @@
     cmake_args=cmake_args,
     keywords="qiskit, simulator, quantum computing, backend",
     zip_safe=False,
-    entry_points={
-        "qiskit.transpiler.translation": [
-            "aer_backend_plugin = qiskit_aer.backends.plugin.aer_backend_plugin:AerBackendPlugin",
-        ]
-    },
 )