[config] Allow !extend/!remove on components without id in schema (#14682)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

tests/components/external_components/common.yaml

@@ -1,6 +1,8 @@
 external_components:
-  - source: github://esphome/esphome@dev
+  - id: my_ext
+    source: github://esphome/esphome@dev
     refresh: 1d
     components: [bh1750]
-  - source: ../../../esphome/components
+  - id: my_local
+    source: ../../../esphome/components
     components: [sntp]

tests/components/external_components/test.esp32-idf.yaml

@@ -1 +1,5 @@
+# WARNING: Using !extend or !remove prevents automatic component grouping in CI, making builds slower.
 <<: !include common.yaml
+
+external_components:
+  - id: !remove my_local