MC-3397: Content Vertical Alignment inside a Container for Tab Item

- add justify content property to tab item xml
- add container element with vertical alignment styles to tab item xml

Author: anthoula

app/code/Magento/PageBuilder/view/base/pagebuilder/content_type/tab_item.xml

@@ -34,7 +34,6 @@
                         <elements>
                             <element name="main">
                                 <style_properties>
-                                    <property name="min_height" source="min_height" converter="Magento_PageBuilder/js/converter/style/remove-px"/>
                                     <property name="background_color" source="background_color" converter="Magento_PageBuilder/js/converter/style/color"/>
                                     <property name="background_image" source="background_image" converter="Magento_PageBuilder/js/converter/style/background-image" preview_converter="Magento_PageBuilder/js/converter/style/preview/background-image"/>
                                     <property name="background_position" source="background_position"/>
@@ -46,6 +45,8 @@
                                     <property name="border_color" source="border_color" converter="Magento_PageBuilder/js/converter/style/color"/>
                                     <property name="border_width" source="border_width" converter="Magento_PageBuilder/js/converter/style/remove-px"/>
                                     <property name="border_radius" source="border_radius" converter="Magento_PageBuilder/js/converter/style/remove-px"/>
+                                    <property name="justify_content" source="justify_content" persist="false"/>
+                                    <property name="min_height" source="min_height" converter="Magento_PageBuilder/js/converter/style/remove-px"/>
                                     <complex_property name="margins" storage_key="margins_and_padding" reader="Magento_PageBuilder/js/property/margins" converter="Magento_PageBuilder/js/converter/style/margins"/>
                                     <complex_property name="padding" storage_key="margins_and_padding" reader="Magento_PageBuilder/js/property/paddings" converter="Magento_PageBuilder/js/converter/style/paddings"/>
                                 </style_properties>
@@ -56,6 +57,13 @@
                                 </attributes>
                                 <css name="css_classes"/>
                             </element>
+                            <element name="container">
+                                <style_properties>
+                                    <property name="justify_content" source="justify_content"/>
+                                    <static_property source="display" value="flex"/>
+                                    <static_property source="flex_direction" value="column"/>
+                                </style_properties>
+                            </element>
                         </elements>
                     </data_mapping>
                 </appearance>