feature: add support for OpenQASM measure on a subset of qubits

[ashlhans]

Issue #, if available:

Description of changes:

• Add a Measure operator that measures the qubit targets specified.
• Removed the Validation error in GateModelQuantumTaskResult to check that measured qubits match the qubit count
• Added Measure to the circuit diagram

Testing done: tox and tox -e integ-tests

Merge Checklist

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General

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

Tests

>>> circ = Circuit().h(0).cnot(0, 1).measure([0])
>>> print(circ)

T  : │  0  │  1  │  2  │
      ┌───┐       ┌───┐ 
q0 : ─┤ H ├───●───┤ M ├─
      └───┘   │   └───┘ 
            ┌─┴─┐       
q1 : ───────┤ X ├───────
            └───┘       
T  : │  0  │  1  │  2  │

>>> print(circ.to_ir("OPENQASM"))

OPENQASM 3.0;
bit[1] b;
qubit[2] q;
h q[0];
cnot q[0], q[1];
b[0] = measure q[0];

• [ ] 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.