Do not unroll gates in basis in add_control

[Cryoris]

Summary

The add_control mechanism currently does some redundant unrolling and re-wrapping of gates that are already in the basis of gates we know how to control. This has knock-on effects and causes #13473, by translating an RZ operation (already supported) to a Phase gate.

This PR avoids this unrolling. As discussed with @alexanderivrii, in the longer term we should consider rewriting this logic entirely and have a controlled gate plugin, which also allows users to supply their own control mechanism.

Details and comments

• There's a failing test (likely since the decomposition now uses the RX-path instead of wrongly the RX->R->U3->U path before), but the unitary is still correct and there are only dangling U(0,0,0) gates.
• Need to add a test for The multi-controlled gate by RZGate().control() is less optimized. #13473

[qiskit-bot]

One or more of the following people are relevant to this code:

• @Qiskit/terra-core

[coveralls]

Pull Request Test Coverage Report for Build 11962255098

Details

• 49 of 51 (96.08%) changed or added relevant lines in 1 file are covered.
• 7 unchanged lines in 3 files lost coverage.
• Overall coverage increased (+0.005%) to 88.94%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
qiskit/circuit/add_control.py	49	51	96.08%

Files with Coverage Reduction	New Missed Lines	%
crates/accelerate/src/unitary_synthesis.rs	1	92.2%
qiskit/circuit/add_control.py	2	95.69%
crates/qasm2/src/lex.rs	4	91.98%

Totals
Change from base Build 11957091507:	0.005%
Covered Lines:	79414
Relevant Lines:	89289

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💛 - Coveralls