Merge remote-tracking branch 'mainline/develop' into S50

Conflicts:
	lib/internal/Magento/Framework/App/Test/Unit/View/Deployment/VersionTest.php

Author: vpaladiychuk

app/code/Magento/Quote/Model/Quote.php

@@ -1538,8 +1538,8 @@ public function addProduct(
         /**
          * Error message
          */
-        if (is_string($cartCandidates)) {
-            return $cartCandidates;
+        if (is_string($cartCandidates) || $cartCandidates instanceof \Magento\Framework\Phrase) {
+            return strval($cartCandidates);
         }
 
         /**

app/code/Magento/Sales/view/adminhtml/web/order/create/scripts.js

@@ -668,6 +668,7 @@ AdminOrder.prototype = {
         if (confirm(confirmMessage)) {
             this.collectElementsValue = false;
             order.sidebarApplyChanges({'sidebar[empty_customer_cart]': 1});
+            this.collectElementsValue = true;
         }
     },