[scheduler] Fix DelayAction cancellation in restart mode scripts (#9646)

tests/integration/fixtures/delay_action_cancellation.yaml

@@ -0,0 +1,24 @@
+esphome:
+  name: test-delay-action
+
+host:
+api:
+  actions:
+    - action: start_delay_then_restart
+      then:
+        - logger.log: "Starting first script execution"
+        - script.execute: test_delay_script
+        - delay: 250ms  # Give first script time to start delay
+        - logger.log: "Restarting script (should cancel first delay)"
+        - script.execute: test_delay_script
+
+logger:
+  level: DEBUG
+
+script:
+  - id: test_delay_script
+    mode: restart
+    then:
+      - logger.log: "Script started, beginning delay"
+      - delay: 500ms  # Long enough that it won't complete before restart
+      - logger.log: "Delay completed successfully"