set default color to tabs titles (mondaycom#386)

Author: Hadas Farhi

src/components/Tabs/Tab/Tab.scss

@@ -38,6 +38,7 @@
     user-select: none;
     margin-bottom: $margin-bottom;
     cursor: pointer;
+    @include theme-prop(color, primary-text-color);
 
     &:focus {
       outline: none;