feature: count circuit operation on circuit or given qubits

[skushagra]

*Issue #1235

Description of changes:
I have added a count_instruction functions that gives you count of an instrcution on a circuit. I have added test cases for the required flow.

Features

• Count instructions by operator type.
• Optional filtering by:
  • Operator name, operator class, or operator instance.
  • Qubits involved in an instruction.
  • Moment types (GATE, GATE_NOISE, MEASURE etc.).
• Supports multi-qubit filtering via:
  • QubitMatch.ANY — instruction on any specified qubit.
  • QubitMatch.ALL — instruction on all specified qubits.
• When both operator and qubit filters are provided, instructions must satisfy both filters (AND).

Merge Checklist

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General

• I have read the CONTRIBUTING doc
• I used the PR title format described in CONTRIBUTING
• I have updated any necessary documentation, including READMEs and API docs (if appropriate)

Tests

• I have added tests that prove my fix is effective or that my feature works (if appropriate)
• I have checked that my tests are not configured for a specific region or account (if appropriate)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[skushagra]

I did not understand much around what can we do for calculating density of operations. I would need more clarification on how should we exactly define this density, and since there can be multiple ways with respect to which density can be calculated like, operations per layer, per qubit etc.

Hence I extracted this into a seprate helper file to prevent bloating the Circuit class. Perhaps more clarification on this would help me to add such a features.

[aniksd-braket]

@skushagra could you also make sure to resolve all comments for the next updated CR

[aniksd-braket]

@skushagra are you still working on this?

[skushagra]

Yes I am, will resolve these comments in a bit

[skushagra]

@aniksd-braket fixed the pending comments, please have a look and let me know if anything else is needed

[aniksd-braket]

This looks good, getting closer to the final product. I am assuming you used AI for creating tests? some of them seem repetitive/unnecessary. can you trim it down and/or consolidate them?