Change IconComponent type to be compatible with MUI5

Signed-off-by: Philipp Hugenroth <philipph@spotify.com>

packages/core-plugin-api/src/icons/types.ts

@@ -33,5 +33,5 @@ import { ComponentType } from 'react';
  * @public
  */
 export type IconComponent = ComponentType<{
-  fontSize?: 'default' | 'small' | 'large';
+  fontSize?: 'inherit' | 'medium' | 'large' | 'small';
 }>;