Remove legacy-editable option from setuptools builds (backport #13059)

[mergify]

Summary

We needed this back when setuptools first introduced the new editable installations, but at this point it should work more correctly without it; our non-CI configurations haven't included it for some time.

Details and comments

Let's just let CI run to ensure there's no further complications from this removal.

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This is an automatic backport of pull request #13059 done by [Mergify](https://mergify.com).

[qiskit-bot]

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[coveralls]

Pull Request Test Coverage Report for Build 10635038469

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 3 unchanged lines in 2 files lost coverage.
• Overall coverage increased (+0.02%) to 89.85%

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Files with Coverage Reduction	New Missed Lines	%
crates/qasm2/src/expr.rs	1	94.02%
crates/qasm2/src/lex.rs	2	93.23%

Totals
Change from base Build 10577165228:	0.02%
Covered Lines:	66922
Relevant Lines:	74482

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💛 - Coveralls