Update result field type for batch results and other small fixes

[kshyatt-aws]

Issue #, if available: N/A

Description of changes: Update result field for batches to match expected behaviour. Fix IR output for gates for OpenQASM. Make delegate in LocalSimulator more flexible to make it easier to extend.

Testing done: Unit tests passed locally.

Merge Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your pull request.

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

• I have installed and run git secrets to make sure I did not commit any sensitive information (passwords or credentials)
• 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.

[codecov]

Codecov Report

Attention: Patch coverage is 42.85714% with 4 lines in your changes missing coverage. Please review.

Project coverage is 88.95%. Comparing base (c998090) to head (40e9c57).

Files	Patch %	Lines
src/local_simulator.jl	20.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #94      +/-   ##
==========================================
- Coverage   89.00%   88.95%   -0.05%     
==========================================
  Files          36       36              
  Lines        3929     3931       +2     
==========================================
  Hits         3497     3497              
- Misses        432      434       +2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.