fix(vue): HMR error (#5460)

* fix HMR error in vue

this fixes `TypeError: originalSlots[slotName] is not a function` error during HMR in vue by ensuring the function exists.

* Update get-children.js

src/vue/get-children.js

@@ -29,6 +29,7 @@ function getChildren(originalSlots = {}, slidesRef, oldSlidesRef) {
   };
 
   Object.keys(originalSlots).forEach((slotName) => {
+    if (typeof originalSlots[slotName] !== 'function') return;
     const els = originalSlots[slotName]();
     getSlidesFromElements(els, slotName);
   });