Fix slow scroll on card detail by setting scrollInertia to 0.

Thanks to cafeoh !

Closes #2179

packages/wekan-scrollbar/jquery.mCustomScrollbar.js

@@ -111,7 +111,7 @@ and dependencies (minified).
 			scrolling inertia
 			values: integer (milliseconds)
 			*/
-			scrollInertia:950,
+			scrollInertia:0,
 			/*
 			auto-adjust scrollbar dragger length
 			values: boolean