Issue #3445290: Created a function that override message theme function and...

Issue #3445290: Created a function that override message theme function and attached it as a library.

Closes #3445290

js/toastify-attach.js

@@ -15,7 +15,10 @@
       gravity: displaySettings[type].gravity,
       position: displaySettings[type].position,
       close: displaySettings[type].close,
-      backgroundColor: 'linear-gradient(' + displaySettings[type].direction + ', ' + displaySettings[type].color + ', ' + displaySettings[type].color2 + ')',
+      style: {
+        background: 'linear-gradient(' + displaySettings[type].direction + ', ' + displaySettings[type].color + ', ' + displaySettings[type].color2 + ')',
+        color: displaySettings[type].text_color,
+      },
       escapeMarkup: false,
       className: `toastify--${type}`,
       progressBar: true,