[core] Fix error on invalid id extend/remove (#12064)

esphome/config.py

@@ -355,6 +355,8 @@ def _get_item_id(item: Any) -> str | Extend | Remove | None:
     if isinstance(item_id, Extend):
         # Remove instances of Extend so they don't overwrite the original item when merging:
         del item[CONF_ID]
+    elif not isinstance(item_id, (str, Remove)):
+        return None
     return item_id
 
 

tests/unit_tests/fixtures/substitutions/05-extend-remove.approved.yaml

@@ -31,3 +31,9 @@ lvgl:
             id: object5
             x: 10
             y: 11
+        - obj:
+            id:
+              - Invalid ID
+        - obj:
+            id:
+              invalid: id

tests/unit_tests/fixtures/substitutions/05-extend-remove.input.yaml

@@ -37,6 +37,10 @@ packages:
                 id: object5
                 x: 10
                 y: 11
+            - obj:
+                id: ["Invalid ID"]
+            - obj:
+                id: {"invalid": "id"}
 
 some_component:
   - id: !extend ${A}