[config:export:*] exclude _core because its site specific (#2975)

Author: enzolutions

src/Command/Config/ExportCommand.php

@@ -91,6 +91,10 @@ protected function execute(InputInterface $input, OutputInterface $output)
             foreach ($this->configManager->getConfigFactory()->listAll() as $name) {
                 $configData = $this->configManager->getConfigFactory()->get($name)->getRawData();
                 $configName =  sprintf('%s.yml', $name);
+
+                // The _core is site-specific, so don't export it.
+                unset($configData['_core']);
+
                 $ymlData = Yaml::encode($configData);
 
                 if ($tar) {

src/Command/Shared/ExportTrait.php

@@ -30,6 +30,9 @@ protected function getConfiguration($configName, $uuid = false)
             unset($config['uuid']);
         }
 
+        // The _core is site-specific, so don't export it.
+        unset($config['_core']);
+
         return $config;
     }