test(noxfile.py): turn off bold and colors (#11172)

ISSUES CLOSED: #11134

## Description

This turns off bold and colors in the terminal, making the output much easier to find substrings.

## Type of Change

- [ X ] Bug fix (non-breaking change which fixes an issue)
- [ X ] Test improvements

## Quality Checklist

- [ ] Code follows the project's coding standards (see CONTRIBUTING.md)
- [ ] All public/protected methods have argument validation
- [ ] Static typing is complete (no `Any` unless justified)
- [ ] `nox -s typecheck` passes with no errors
- [ ] `nox -s lint` passes with no errors
- [ ] Unit tests written/updated (Behave scenarios in `features/`)
- [ ] Integration tests written/updated (Robot suites in `robot/`) if applicable
- [ ] Coverage remains above 85% (`nox -s coverage_report`)
- [ ] No security issues introduced (`nox -s security_scan`)
- [ ] No dead code introduced (`nox -s dead_code`)
- [ ] Documentation updated if behavior changed

## Testing

I ran `nox -e unit_tests` locally, and I verified that the seven errors that had existed no longer exist.

### Test Commands Run

```bash
nox -s unit_tests       # Behave tests
nox -s typecheck        # Type checking
nox -s lint             # Linting
nox -s coverage_report  # Coverage
```

## Related Issues

ISSUES CLOSED: #11134

## Implementation Notes

This change to the terminal had been done outside the program in git.cleverthis.com, so the problems never showed up there.

Reviewed-on: #11172
Reviewed-by: Luis Mendes <luis.mendes@cleverthis.com>

noxfile.py

@@ -179,6 +179,9 @@ def unit_tests(session: nox.Session):
     template_path = _create_template_db(session)
     session.env["CLEVERAGENTS_TEMPLATE_DB"] = template_path
 
+    # Remove ANSI escape codes.
+    session.env["TERM"] = "dumb"
+
     behave_cmd = session.bin + "/behave-parallel"
     parallel_args = _behave_parallel_args(session.posargs)