Merge forwardport of #12755 to 2.3-develop branch

Applied pull request patch https://github.com/magento/magento2/pull/12755.patch (created by @virtual97) based on commit(s):
  1. 2ccb374
  2. 288d0d4
  3. e78ea61

Fixed GitHub Issues in 2.3-develop branch:
  - #12294: Bug: Adding Custom Attribute - The value of Admin scope can't be empty (reported by @webscot)

app/code/Magento/Catalog/view/adminhtml/templates/catalog/product/attribute/options.phtml

@@ -57,7 +57,7 @@ $stores = $block->getStoresSortedBySortOrder();
  <input type="hidden" id="option-count-check" value="" />
  </div>
  <script id="row-template" type="text/x-magento-template">
-  <tr>
+ <tr <% if (data.rowClasses) { %>class="<%- data.rowClasses %>"<% } %>>
  <td class="col-draggable">
  <?php if (!$block->getReadOnly() && !$block->canManageOptionDefaultOnly()): ?>
  <div data-role="draggable-handle" class="draggable-handle"

app/code/Magento/Catalog/view/adminhtml/web/js/options.js

@@ -24,6 +24,7 @@ define([
  totalItems: 0,
  rendered: 0,
  template: mageTemplate('#row-template'),
+ newOptionClass: 'new-option',
  isReadOnly: config.isReadOnly,
  add: function (data, render) {
  var isNewOption = false,
@@ -32,7 +33,8 @@ define([
  if (typeof data.id == 'undefined') {
  data = {
  'id': 'option_' + this.itemCount,
- 'sort_order': this.itemCount + 1
+ 'sort_order': this.itemCount + 1,
+ 'rowClasses': this.newOptionClass
  };
  isNewOption = true;
  }
@@ -84,6 +86,10 @@ define([
  this.totalItems--;
  this.updateItemsCountField();
  }
+
+ if (element.hasClassName(this.newOptionClass)) {
+ element.remove();
+ }
  },
  updateItemsCountField: function () {
  $('option-count-check').value = this.totalItems > 0 ? '1' : '';