fix: use empty ResourcesToBuildCollector in ECS sync _build_from_scratch

collect_build_resources() only handles functions/layers and raises
ResourceNotFound for ECS/AgentCore resource IDs. Since
build_container_images() doesn't depend on resources_to_build,
pass an empty collector instead.

Author: singledigit

samcli/lib/sync/flows/ecs_container_sync_flow.py

@@ -9,7 +9,7 @@
 from samcli.lib.build.app_builder import ApplicationBuilder, ApplicationBuildResult
 from samcli.lib.build.build_graph import ContainerBuildDefinition
 from samcli.lib.package.ecr_uploader import ECRUploader
-from samcli.lib.providers.provider import Stack
+from samcli.lib.providers.provider import ResourcesToBuildCollector, Stack
 from samcli.lib.providers.sam_container_provider import SamContainerServiceProvider
 from samcli.lib.sync.sync_flow import ApiCallTypes, ResourceAPICall, SyncFlow
 from samcli.local.docker.utils import get_validated_container_client
@@ -109,11 +109,7 @@ def _build_from_scratch(self) -> None:
         )
 
         builder = ApplicationBuilder(
-            (
-                self._build_context.collect_build_resources(self._resource_identifier)
-                if hasattr(self._build_context, "collect_build_resources")
-                else self._build_context.get_resources_to_build()
-            ),
+            ResourcesToBuildCollector(),
             self._build_context.build_dir,
             self._build_context.base_dir,
             self._build_context.cache_dir,