The plugin loader startup logs aren't following the logger convention,
which makes them hard to work with when post-processing logs.
The appended error message is also not useful since we're logging a
Event variant raw (which either outputs {} or nonsense like { isTrusted:
etc }).
Make the plugin "loaded" and "error" logs adhere to logger conventions.
In the future, the error log could use some tuning - there's no useful
info about root cause here.
