Use Claro as the admin theme

config/sync/block.block.claro_primary_local_tasks.yml

@@ -0,0 +1,22 @@
+uuid: 6665d4bb-c9a8-4143-96d5-754b448422cc
+langcode: en
+status: true
+dependencies:
+  theme:
+    - claro
+_core:
+  default_config_hash: 7cvXIzw8NabmQCWMPqBz0mvIQZzXUZB3OeOTa5eqbCo
+id: claro_primary_local_tasks
+theme: claro
+region: header
+weight: 0
+provider: null
+plugin: local_tasks_block
+settings:
+  id: local_tasks_block
+  label: 'Primary tabs'
+  provider: core
+  label_display: '0'
+  primary: true
+  secondary: false
+visibility: {  }