fix: Make GPhase more efficient

[speller26]

GPhase applies to no qubits rather than all qubits when no targets are supplied.

Issue #, if available:

Description of changes:

Testing done:

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (1187ce9) to head (59f6f4c).

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #245   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           48        48           
  Lines         3781      3779    -2     
  Branches       917       916    -1     
=========================================
- Hits          3781      3779    -2     

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