Extended support for different V2 transpilers from different backends. (backport #879)

[mergify]

Summary

Extended support for different V2 transpilers from different Aer backends.
Closes #872.

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This is an automatic backport of pull request #879 done by [Mergify](https://mergify.com).

[edoaltamura]

Now, only one check can be run - strange! We still need the others to pass though.

[coveralls]

Pull Request Test Coverage Report for Build 12417127938

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 6 (0.0%) changed or added relevant lines in 2 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.07%) to 90.635%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
qiskit_machine_learning/neural_networks/estimator_qnn.py	0	3	0.0%
qiskit_machine_learning/neural_networks/sampler_qnn.py	0	3	0.0%

Files with Coverage Reduction	New Missed Lines	%
qiskit_machine_learning/algorithms/trainable_model.py	1	89.09%

Totals
Change from base Build 12356469741:	-0.07%
Covered Lines:	4365
Relevant Lines:	4816

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💛 - Coveralls