Default init plugin was not properly raising when called with an invalid optimization level (backport #12170)

[mergify]

While @Randl was working on extending types in the qiskit.transpile module, he found a bug in which the default init plugin was not properly raising when called with an invalid optimization level. Thanks @Randl !

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This is an automatic backport of pull request #12170 done by Mergify.

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[coveralls]

Pull Request Test Coverage Report for Build 8668344954

Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage increased (+0.01%) to 89.32%

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Files with Coverage Reduction	New Missed Lines	%
crates/qasm2/src/lex.rs	1	92.62%

Totals
Change from base Build 8598647194:	0.01%
Covered Lines:	58911
Relevant Lines:	65955

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💛 - Coveralls