fix: prevent repeated measurements on a qubit

[ashlhans]

Issue #, if available:

Description of changes:

Currently, the following circuits are allowed where a qubit appears to be measured more than once:

circ = Circuit().h(0).cnot(0, 1).rx(0, 0.9).ry(1, 0.2).measure([0,0,0,0])

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

A qubit can only be measured once so we should raise an error for repeated qubits in a measure instruction.

Testing done: tox and tox -e integ-tests

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[codecov[bot]]

Codecov Report

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

Project coverage is 100.00%. Comparing base (d5580dc) to head (3444e18).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #937 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 133 133 Lines 8901 8905 +4 Branches 2004 2006 +2 ========================================= + Hits 8901 8905 +4 ```

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