FIX: Handle JSON markdown format exceptions

[meisman-ms]

Description

This PR handles variations of markdown formatted JSON responses which were not previously handled, resulting in exceptions (see #413 for details).

I decided to create a few helper functions in order to maintain code clarity while providing a more robust and extensible solution. Should new or additional patterns need handled in the future, it's likely that modifying the regex to include the new pattern will be sufficient without necessitating logic modifications.

Technical Details

Originally, only one specific case was handled, so if the markdown syntax was not in this format ```json\n .... \n```, it would result in an exception. Now the handler can resolve any combination of the following start and end notations, as well as scenarios where only the start or end markdown was present.

Start Notations Handled: ```json\n, `json\n, ```\n, `\n, ```json, `json, ```, `, json, json\n
End Notations Handled: \n```, \n`, ```, `

Finally, after removing any markdown, I added validation for proper JSON format. If the format is still invalid, another attempt will be taken to extract any valid JSON object or array. This could be useful in many cases; for instance, if the starting markdown tag had a typo such as ```jsn\n, the helper function which removes the starting tag would only remove the ```, so it would still be improper JSON without this final check.

Tests and Documentation

I added unit tests for the new functions I created, as well as for the original exception handler function which was not previously tested. I added comments for each function to document the purpose and usage.

Code Coverage

Coverage Before

### Combined Coverage:

### File Specific Coverage:
### Uncovered lines (related to this work item):

Coverage After

### Combined Coverage:

### File Specific Coverage:

### New File:

### Previously Untested:

Validation

• All unit tests are passing
• Code coverage after >= before
• Pre-commit hooks / lint passed

@romanlutz @nina-msft