fix(svg-icons): default icons color (#8382)

Uses the same color as defined by the `color` property of the `video-js` class to apply to `svg icons` for easy customization

- set `fill` property to `currentColor`

Co-authored-by: mister-ben <git@misterben.me>

src/css/_icons.scss

@@ -11,7 +11,7 @@
   background-repeat: no-repeat;
   background-position: center;
 
-  fill: #FFFFFF;
+  fill: currentColor;
   height: 1.8em;
   width: 1.8em;