fix: Pin amazon-braket-sdk version to 1.81.0

[rmshaffer]

Issue #, if available: https://github.com/amazon-braket/autoqasm/issues/34

Description of changes: This is a temporary workaround for https://github.com/amazon-braket/autoqasm/issues/34 which will allow CI to pass again while a full fix is developed.

Testing done: tox and CI

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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 (e2bb431) to head (16a20b2). Report is 7 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #35 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 49 49 Lines 2090 2090 Branches 345 345 ========================================= Hits 2090 2090 ```

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