chore: remove unused build dir (#1379)

# What does this PR do?
[Provide a short summary of what this PR does and why. Link to relevant
issues if applicable.]

- From old PR, it use `BUILDS_BASE_DIR` in
`llama_stack/cli/stack/configure.py`(removed).
https://github.com/meta-llama/llama-stack/pull/371/files
- Based on the current `build` code, it should only use
`DISTRIBS_BASE_DIR` to save it.

46b0a404e8/llama_stack/cli/stack/_build.py (L298)

46b0a404e8/llama_stack/cli/stack/_build.py (L301)
Pls correct me if I am understand incorrectly.
So it should no need to use in `run` now.

[//]: # (If resolving an issue, uncomment and update the line below)
[//]: # (Closes #[issue-number])

## Test Plan
[Describe the tests you ran to verify your changes with result
summaries. *Provide clear instructions so the plan can be easily
re-executed.*]

[//]: # (## Documentation)

Signed-off-by: reidliu <reid201711@gmail.com>
Co-authored-by: reidliu <reid201711@gmail.com>

llama_stack/cli/stack/run.py

@@ -79,12 +79,8 @@ class StackRun(Subcommand):
     def _run_stack_run_cmd(self, args: argparse.Namespace) -> None:
         import yaml
 
-        from llama_stack.distribution.build import ImageType
         from llama_stack.distribution.configure import parse_and_maybe_upgrade_config
-        from llama_stack.distribution.utils.config_dirs import (
-            BUILDS_BASE_DIR,
-            DISTRIBS_BASE_DIR,
-        )
+        from llama_stack.distribution.utils.config_dirs import DISTRIBS_BASE_DIR
         from llama_stack.distribution.utils.exec import formulate_run_args, run_with_pty
 
         config_file = Path(args.config)
@@ -97,14 +93,6 @@ class StackRun(Subcommand):
             if config_file.exists():
                 template_name = args.config
 
-        if not config_file.exists() and not has_yaml_suffix:
-            # check if it's a build config saved to conda dir
-            config_file = Path(BUILDS_BASE_DIR / ImageType.conda.value / f"{args.config}-run.yaml")
-
-        if not config_file.exists() and not has_yaml_suffix:
-            # check if it's a build config saved to container dir
-            config_file = Path(BUILDS_BASE_DIR / ImageType.container.value / f"{args.config}-run.yaml")
-
         if not config_file.exists() and not has_yaml_suffix:
             # check if it's a build config saved to ~/.llama dir
             config_file = Path(DISTRIBS_BASE_DIR / f"llamastack-{args.config}" / f"{args.config}-run.yaml")