[Glitch] Rewrite actions/modal and reducers/modal with typescript

Port 38c6216082 to glitch-soc

Signed-off-by: Claire <claire.github-309c@sitedethib.com>

app/javascript/flavours/glitch/actions/compose.js

@@ -416,7 +416,10 @@ export function initMediaEditModal(id) {
       id,
     });
 
-    dispatch(openModal('FOCAL_POINT', { id }));
+    dispatch(openModal({
+      modalType: 'FOCAL_POINT',
+      modalProps: { id },
+    }));
   };
 }