Adds use composition-api to composable due to @vue/composition-api sh…

…ortcomings in vue2

lib/composition-api.js

@@ -0,0 +1,4 @@
+import Vue from 'vue';
+import VueCompositionAPI from '@vue/composition-api';
+
+Vue.use(VueCompositionAPI);

lib/useKWindowDimensions.js

@@ -1,5 +1,19 @@
+import './composition-api'; //Due to @vue/composition-api shortcomings, add plugin prior to use in kolibri, studio and tests
 import { onBeforeUnmount, onMounted, ref } from '@vue/composition-api';
 
+/** Window dimensions */
+const windowWidth = ref(null);
+const windowHeight = ref(null);
+
+/**
+ * Update window width and height
+ */
+const updateWindow = () => {
+  const metrics = windowMetrics();
+  windowWidth.value = metrics.width;
+  windowHeight.value = metrics.height;
+};
+
 /**
  * Returns window inner width and height
  * @returns {Object} The window's inner width and height
@@ -44,18 +58,6 @@ function removeWindowListener(handler) {
 }
 
 export default function useKWindowDimensions() {
-  const windowWidth = ref(null);
-  const windowHeight = ref(null);
-
-  /**
-   * Update window width and height
-   */
-  const updateWindow = () => {
-    const metrics = windowMetrics();
-    windowWidth.value = metrics.width;
-    windowHeight.value = metrics.height;
-  };
-
   onMounted(() => {
     addWindowListener(updateWindow);
   });