qml.execute no longer accepts mcm_config argument

[andrijapau]

Context:

Further qml.workflow clean-up. This enables qml.execute to mimic the signature of QNode. This ensures that we don't get incompatible configurations because we have two different entry points.

Description of the Change:

Eco-System

• Catalyst: QNode.execute_kwargs no longer has mcm_config key catalyst#1452
• Lightning: No instances of deprecated code found.
• QML Demos: No instances of deprecated code found.

Plugins

• Pennylane-AQT: No instances of deprecated code found.
• Pennylane-Qiskit: No instances of deprecated code found.
• Pennylane-IonQ: No instances of deprecated code found.
• Pennylane-Qrack: No instances of deprecated code found.
• Pennylane-Cirq: No instances of deprecated code found.
• Pennylane-Qulacs: No instances of deprecated code found.

Introduce kwargs postselect_mode and mcm_method to qml.execute signature. Raise deprecation warning to user if they try to use mcm_config kwarg.

Side-effect: Had to xfail any tests that had to do with Catalyst since they assume certain keys from the QNode.execute_kwargs. Will be reverted in #6873.

Benefits:

Keyword parity with qml.QNode.

Possible Drawbacks: None identified.

[sc-80541]

[albi3ro]

We should also add an entry to deprecations.rst.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.54%. Comparing base (61dbc71) to head (a7a73b7).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6807      +/-   ##
==========================================
- Coverage   99.59%   99.54%   -0.05%     
==========================================
  Files         477      477              
  Lines       45233    45237       +4     
==========================================
- Hits        45050    45033      -17     
- Misses        183      204      +21     

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[JerryChen97]

LGTM!