13911 | Add ignoring of RuntimeWarning of aer in GenericBackendV2 test

[LeanderCS]

Summary

Because the aer isn't available on all envs, the test logs get flooded with meaningless DeprecationWarnings.

This PR adds that this type of error for the affected class gets ignored in the tests.

Fixes #13911

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[coveralls]

Pull Request Test Coverage Report for Build 13475630823

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 7 unchanged lines in 2 files lost coverage.
• Overall coverage increased (+0.008%) to 88.129%

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Files with Coverage Reduction	New Missed Lines	%
crates/accelerate/src/unitary_synthesis.rs	2	94.29%
crates/qasm2/src/lex.rs	5	92.73%

Totals
Change from base Build 13469145802:	0.008%
Covered Lines:	78403
Relevant Lines:	88964

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💛 - Coveralls