chore: use parent theme callback

Co-authored-by: Florent <ze-flo@users.noreply.github.com>

Author: geotrev

packages/notifications/src/elements/global-alert/GlobalAlert.tsx

@@ -44,7 +44,7 @@ const GlobalAlertComponent = forwardRef<HTMLDivElement, IGlobalAlertProps>(
     );
 
     return (
-      <ThemeProvider theme={lightTheme}>
+      <ThemeProvider theme={theme => ({...theme, colors: { ...theme.colors, base: 'light' })}>
         <GlobalAlertContext.Provider value={useMemo(() => ({ type }), [type])}>
           {/* [2] */}
           {/* eslint-disable-next-line jsx-a11y/prefer-tag-over-role */}