Adds a json extraction function, which will allow us to properly parse brackets that jsonAdapter outputs:

Before, we would use a regex string that naively matches curly braces, but now we have a smarter extractor that takes the first full object.

We always pass this object to json_repair after.

{
  "reasoning": "think step by step",
  "issue_list": [
    {
      "issue_type": "some type",
      "severity_level": "fatal",
      "problem_code_snippet": "if (user) {"
    }
  ]
}

Would break before because of the unclosed bracket inside the code snippet.

This will also allow us to remove the regex dependency in a follow on PR.

Fixes #8759