OEL-1167: Place the main page content block to ensure block order placement.

modules/oe_whitelabel_multilingual/config/optional/block.block.oe_whitelabel_main_page_content.yml

+langcode: en
+status: true
+dependencies:
+  module:
+    - system
+  theme:
+    - oe_whitelabel
+id: oe_whitelabel_main_page_content
+theme: oe_whitelabel
+region: content
+weight: 1
+provider: null
+plugin: system_main_block
+settings:
+  id: system_main_block
+  label: 'Main page content'
+  label_display: '0'
+  provider: system
+visibility: {  }