Stop failing image refreshing on "warm-up" failure (#25046)

The "warm-up" buld for parallel images might fail when you run
it locally, but this should be ignored, because it is really only
needed at the CI when we want to make sure that several parallel
builds do not try to create the same buildx container.

It's safe to ignore any failure at the warm-up stage.

dev/breeze/src/airflow_breeze/utils/docker_command_utils.py

@@ -703,11 +703,11 @@ def warm_up_docker_builder(image_params: CommonBuildParams, verbose: bool, dry_r
         dry_run=dry_run,
         cwd=AIRFLOW_SOURCES_ROOT,
         text=True,
+        check=False,
         enabled_output_group=True,
     )
     if warm_up_command_result.returncode != 0:
         get_console().print(
-            f"[error]Error {warm_up_command_result.returncode} when warming up builder:"
+            f"[warning]Warning {warm_up_command_result.returncode} when warming up builder:"
             f" {warm_up_command_result.stdout} {warm_up_command_result.stderr}"
         )
-        sys.exit(warm_up_command_result.returncode)