fix: use tracking-based is_mcm_dependent in AbstractProgramContext

[rmshaffer]

Issue #, if available:

Description of changes:

AbstractProgramContext.is_mcm_dependent now uses the scope-tracking machinery that already exists on the base class (_mcm_dependent_scopes, _is_name_mcm_dependent, _referenced_identifiers). The identical override on ProgramContext is removed.

Subclasses that use a different tracking model (e.g.qiskit-braket-provider's _QiskitProgramContext, which tracks measured bits in its own set) should override is_mcm_dependent to reflect that model. A companion change in qiskit-braket-provider does exactly this.

Testing done:

• All existing unit tests pass.
• Updated test_is_mcm_dependent_defaults_to_* to reflect the new semantics (no measurements tracked → not MCM-dependent).
• Verified the pending qiskit-braket-provider changes in fix: unify MCM-dependency check in _QiskitProgramContext qiskit-braket-provider#323 pass on their own against the released default simulator, as well as against this branch.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (3efd89c) to head (f479cd4).

Additional details and impacted files

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##              main      #366   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files           49        49           
  Lines         4894      4895    +1     
  Branches       565       565           
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+ Hits          4894      4895    +1     

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[speller26]

Implemented a different fix in #367

[speller26]

I actually originally had this default, but decided against it because I don't want the abstract class to bias towards an implementation (in this case translation)

[rmshaffer]

Yeah, makes sense. Happy to close this PR in favor of #367