fix(developer): lm compiler handle missing line no in errors

Fixes #8443.

Will cherry-pick to stable-16.0.

The regex for matching error messages has an optional section for
the file/line detail (line 54):

```regex
^(?:(.+) \((\d+)\): )?<snip>
```

The code that parses the results did not account for this being
optional, which would cause a crash if the error message did not include
this information.