Add console logs to debug windows build

Author: akila-i

kolibri/plugins/epub_viewer/assets/src/views/SettingsSideBar.vue

@@ -262,7 +262,17 @@
           this.$emit('setTheme', this.themes.WHITE); // apply the default theme
         }
         this.$nextTick(() => {
-          this.$refs.addCustomThemeButton.$refs.button.focus();
+          console.log('refs', this.$refs);
+          console.log('refs.addCustomThemeButton', this.$refs.addCustomThemeButton);
+          console.log('refs.addCustomThemeButton.$refs', this.$refs.addCustomThemeButton.$refs);
+          console.log(
+            'refs.addCustomThemeButton.$refs.button',
+            this.$refs.addCustomThemeButton.$refs.button
+          );
+
+          if (this.$refs.addCustomThemeButton && this.$refs.addCustomThemeButton.$refs.button) {
+            this.$refs.addCustomThemeButton.$refs.button.focus();
+          }
         });
       },
     },