add ImageCaption context to share button component

Author: marjisound

dotcom-rendering/src/components/GalleryCaption.tsx

@@ -94,7 +94,7 @@ export const GalleryCaption = ({
 					format={format}
 					pageId={pageId}
 					webTitle={webTitle}
-					context="ArticleMeta"
+					context="ImageCaption"
 				/>
 			</Island>
 		</figcaption>

dotcom-rendering/src/components/ShareButton.importable.tsx

@@ -24,7 +24,7 @@ type Props = {
 
 type ButtonKind = 'native' | 'copy' | 'email';
 
-type Context = 'ArticleMeta' | 'LiveBlock' | 'SubMeta';
+type Context = 'ArticleMeta' | 'LiveBlock' | 'SubMeta' | 'ImageCaption';
 
 const sharedButtonStyles = (sizeXSmall: boolean) => css`
 	transition: none;