Fix ControlledQubitUnitary consistency with program capture

[andrijapau]

Context:

The ControlledQubitUnitary operator previously exhibited inconsistent behavior when capture was enabled. This PR addresses the issue by updating and overwriting the _primitive_bind_call class method to handle the operator's unique call signature correctly.

Description of the Change:

Important Consequence: If the user does not specify wires but provides more than one control_wire, the wires will now be inferred from the input dimensions of the base operator. This is necessary to get program capture working. Once control_wires is deprecated, this can be improved.

The behaviour, with or without capture enabled, is the following,

>>> import pennylane as qml
>>> A = [[0, 1], [1, 0]]
>>> qml.ControlledQubitUnitary(A, [0, 1, 2])
Controlled(QubitUnitary(array([[0, 1],[1, 0]]), wires=[2]), control_wires=[0, 1])

>>> qml.ControlledQubitUnitary(A, 0, 1)
Controlled(QubitUnitary(array([[0, 1],[1, 0]]), wires=[1]), control_wires=[0])

>>> qml.ControlledQubitUnitary(A, control_wires=[0,1], wires=None)
Controlled(QubitUnitary(array([[0, 1],[1, 0]]), wires=[1]), control_wires=[0])

>>> qml.ControlledQubitUnitary(A, control_wires=0, wires=None)
"TypeError: Must specify a set of wires. None is not a valid `wires` label."

Benefits:

Code is now behaving consistently when qml.capture is enabled or disabled.

Possible Drawbacks: Example (3) above isn't necessarily expected. This should be sorted out when control_wires is deprecated.

Related GitHub Issues: Fixes #6675

[sc-79808]

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.62%. Comparing base (97f2cb5) to head (9c12a1a).
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Additional details and impacted files

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  Coverage   99.62%   99.62%           
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  Lines       45025    45045   +20     
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+ Hits        44856    44876   +20     
  Misses        169      169           

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[astralcai]

I would actually expect

qml.ControlledQubitUnitary(A, control_wires=[0,1], wires=None)

to raise the same error as

qml.ControlledQubitUnitary(A, control_wires=0, wires=None)

[JerryChen97]

I would actually expect

qml.ControlledQubitUnitary(A, control_wires=[0,1], wires=None)

to raise the same error as

qml.ControlledQubitUnitary(A, control_wires=0, wires=None)

Why are you still working when on vacation (

[PietropaoloFrisoni]

🚀