fix: add missing styles for charts tooltips

Author: mrholek

src/scss/style.scss

@@ -3,6 +3,7 @@
 
 // Import styles
 @import "@coreui/coreui/scss/coreui";
+@import "@coreui/chartjs/scss/coreui-chartjs";
 
 // Vendors
 @import "vendors/simplebar";