chore(eui): improve EuiCallout size prop type (#8917)

Author: weronikaolejniczak

packages/eui/src/components/call_out/call_out.tsx

@@ -32,9 +32,10 @@ export const COLORS = [
 export type Color = (typeof COLORS)[number];
 
 export const HEADINGS = ['h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'p'] as const;
-type Heading = (typeof HEADINGS)[number];
+export type Heading = (typeof HEADINGS)[number];
 
-type Size = 's' | 'm';
+export const SIZES = ['s', 'm'] as const;
+export type Size = (typeof SIZES)[number];
 
 export type EuiCallOutProps = CommonProps &
   Omit<HTMLAttributes<HTMLDivElement>, 'title' | 'color'> & {