Fix possibility of falsy zero for work_wires in templates

[andrijapau]

Context:

Follow up to #6713.

Previously, work_wires=0 was incorrectly being mapped to an empty list,

>>> qml.Adder(1, x_wires=(), mod=1, work_wires=0)
TypeError: object of type 'int' has no len()

Now, we have it properly handled,

>>> qml.Adder(1, x_wires=(), mod=1, work_wires=0)
Adder(wires=[0])
>>> qml.Adder(1, x_wires=(), mod=1, work_wires=None)
ValueError: Adder: wrong number of wires. At least one wire has to be given.

Description of the Change:

Source Code

Change the faulty logic of work_wires = work_wires or () which will fail if work_wires=0.

Test Suite

Added tests to templates that allow single work wires, ensuring work_wires=0 can be passed.

Benefits: Fixes possibility of falsy zero logic in work_wires.

Possible Drawbacks: None.

[sc-80454]

[albi3ro]

I'm wondering if these are worth tests to prevent this mistake from happening again?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.62%. Comparing base (cffa08a) to head (90e820c).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6720      +/-   ##
==========================================
- Coverage   99.62%   99.62%   -0.01%     
==========================================
  Files         476      476              
  Lines       44740    44733       -7     
==========================================
- Hits        44571    44564       -7     
  Misses        169      169              

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[lillian542]

LGTM!

[KetpuntoG]

🙌