### Is there an existing issue for this?

- [X] I have searched the existing issues

### Feature description

I prefer not to use the real regions when doing tests or local stuff to make sure that if it accidentally picks up real credentials, it won't actually create or interact with resources in AWS. This used to work find in localstack - I even dug through the code to find that there is an option in the `RegionStore` to disable validation of the region string. At some point, you removed any way to disable that validation though, which means it just fails all requests using a custom region.

### 🧑‍💻 Implementation

There's already a flag that is passed to the account and region store constructors to disable validation. Seems like an environment variable or configuration flag to disable validation could be propagated.

### Anything else?

_No response_
"""Returns directories used for when running localstack CLI commands from the host system. Unlike
        ``for_container``, these here need to be cross-platform. Ideally, this should not be needed at all,
        because the localstack runtime and CLI do not share any control paths. There are a handful of
        situations where directories or files may be created lazily for CLI commands. Some paths are
        intentionally set to None to provoke errors if these paths are used from the CLI - which they
        shouldn't. This is a symptom of not having a clear separation between CLI/runtime code, which will
        be a future project."""
        import tempfile
        from localstack.utils import files
        tmp_dir = os.path.join(tempfile.gettempdir(), "localstack-cli")
        cache_dir = (files.cache_dir() / "cli").absolute()
        return Directories(
            static_libs=None,
            var_libs=None,
            cache=str(cache_dir),  
            tmp=tmp_dir,
            functions=None,
            data=os.path.join(tmp_dir, "state"),  
            logs=os.path.join(tmp_dir, "logs"),  
            config=None,  
            init=None,
        )
    def mkdirs(self):