[lldb][Platform] Use the module's FileSpec instead of the script's FileSpec when checking LoadScriptFromSymFile setting (#191473)
We were incorrectly passing the script's `FileSpec` into
`GetScriptLoadStyleForModule`. Meaning if a script name wasn't actually
the same as the module name, the `target.auto-load-scripts-for-modules`
didn't take effect.
This patch passes the module's `FileSpec` instead. For `dSYM`s we save
the original `FileSpec` because the loop tries to strip extensions until
it finds a script. But we still want to use the module's name.
**AI Usage**:
- Used Claude to write the unit-test skeletons. Then reviewed/adjusted
them manually