[meta] Improve the accuracy of the component model

[suhaibmujahid]

[suhaibmujahid]

@sylvestre noticed that the model tends to wrongly classify bugs into the Core::Widget: Gtk component. Here are some examples:

• https://bugzilla.mozilla.org/show_bug.cgi?id=1902245#c2
• https://bugzilla.mozilla.org/show_bug.cgi?id=1853497#c1

[marco-c]

@sylvestre noticed that the model tends to wrongly classify bugs into the Core::Widget: Gtk component. Here are some examples:

* https://bugzilla.mozilla.org/show_bug.cgi?id=1902245#c2

* https://bugzilla.mozilla.org/show_bug.cgi?id=1853497#c1

I bet it's because:

• the "User Agent" mentions Linux;
• Linux is very rare;
• most bugs opened by Linux users are about GTK.

So the "safe bet" for the model is to assign GTK to all bugs mentioning Linux :)

[marco-c]

Another option for improving the model is to use a ML classifier (e.g. using #3761) and then an ensemble of the ML classifier and the xgboost classifier.