chore: remove build.py

# What does this PR do?


## Test Plan

tests/unit/distribution/test_build_path.py

@@ -1,40 +0,0 @@
-# Copyright (c) Meta Platforms, Inc. and affiliates.
-# All rights reserved.
-#
-# This source code is licensed under the terms described in the LICENSE file in
-# the root directory of this source tree.
-
-from pathlib import Path
-
-from llama_stack.cli.stack._build import (
-    _run_stack_build_command_from_build_config,
-)
-from llama_stack.core.datatypes import BuildConfig, DistributionSpec
-from llama_stack.core.utils.image_types import LlamaStackImageType
-
-
-def test_container_build_passes_path(monkeypatch, tmp_path):
-    called_with = {}
-
-    def spy_build_image(build_config, image_name, distro_or_config, run_config=None):
-        called_with["path"] = distro_or_config
-        called_with["run_config"] = run_config
-        return 0
-
-    monkeypatch.setattr(
-        "llama_stack.cli.stack._build.build_image",
-        spy_build_image,
-        raising=True,
-    )
-
-    cfg = BuildConfig(
-        image_type=LlamaStackImageType.CONTAINER.value,
-        distribution_spec=DistributionSpec(providers={}, description=""),
-    )
-
-    _run_stack_build_command_from_build_config(cfg, image_name="dummy")
-
-    assert "path" in called_with
-    assert isinstance(called_with["path"], str)
-    assert Path(called_with["path"]).exists()
-    assert called_with["run_config"] is None