refactor: delete redundant tippy css

Author: woothu

scss/vendors/tippyjs/_mixins.scss

@@ -1,6 +1,4 @@
 $namespace-prefix: 'tippy' !default;
 $placements: 'top', 'bottom', 'left', 'right';
 $origins: bottom, top, right, left;
-$backdrop-origins: 0% 25%, 0% -50%, 50% 0%, -50% 0%;
-$backdrop-border-radii: 40% 40% 0 0, 0 0 30% 30%, 50% 0 0 50%, 0 50% 50% 0;
 $arrow-size: 16px;