Add `mcm_method="single-branch-statistics"` for the default Catalyst MCM behaviour

[mudit2812]

Context: As name says.

Description of the Change:

• Add new mcm_method "single-branch-statistics" used to request the original Catalyst way of performing mid-circuit measurements, wherein only a single branch of the execution tree is explored.
• Raise an error if calling a qnode with mcm_method="single-branch-statistics" when not using qml.qjit.
• QNode.__init__ now uses a MCMConfig dataclass for MCM config arguments
• Updated capture module to work with the updates to QNode.
• Added new metaclass ABCCaptureMeta in the capture module to use as the metaclass for MeasurementProcess and Operator. This way, we don't need to create metaclasses local to the files to which those classes belong.

Benefits:

Possible Drawbacks:

Related GitHub Issues:

[mudit2812]

@trbromley Since this is really for catalyst functionality, I'm wondering if I should or should not mention this new mcm_method in the measurements.rst file.

[mudit2812]

Looks good to me but I think the doc needs to be updated right?

Just waiting for @trbromley 's input about that since this is a mcm method specific to Catalyst, so I'm not sure if the docs should be here or in Catalyst.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 99.66%. Comparing base (4600c22) to head (8f6fb46). Report is 259 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #5833 +/- ## ========================================== - Coverage 99.67% 99.66% -0.01% ========================================== Files 417 417 Lines 39978 39692 -286 ========================================== - Hits 39847 39559 -288 - Misses 131 133 +2 ```

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[mudit2812]

[sc-65684]