Quit Playwright Node.js server on cleanup

DESTROY closed the browser but not the handle, leaving the Node.js
playwright_server process running after tests finished.

Author: sunnavy

lib/RT/Test/Playwright.pm

@@ -958,6 +958,7 @@ sub DESTROY {
     $self->{page}->close() if $self->{page};
     $self->{context}->close() if $self->{context};
     $self->{browser}->close() if $self->{browser};
+    $self->{handle}->quit() if $self->{handle};
 }
 
 RT::Base->_ImportOverlays();