Fix sass deprecation warnings

[LukasHirt]

During build, we are getting several sass deprecation warnings. We need to adjust the code.

Deprecation Warning [global-builtin]: In future versions of Sass, round() will be interpreted as a CSS round() calculation. This requires an explicit modulus when rounding numbers with units. If you want to use the Sass function, call math.round() instead.

See https://sass-lang.com/d/import

  ╷
4 │   width: round(calc($oc-size-icon-default * $factor / 2)) * 2;
  │          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  ╵
    packages/design-system/src/components/OcSpinner/OcSpinner.vue 4:10  oc-spinner-size()
    packages/design-system/src/components/OcSpinner/OcSpinner.vue 8:3   root stylesheet