Merge pull request galaxyproject#15657 from bernt-matthias/topic/mull…

…ed-build-local

build_mulled: also use namespace for building singularity images

lib/galaxy/tool_util/deps/container_resolvers/mulled.py

@@ -786,6 +786,7 @@ def __init__(
             "channels": self._get_config_option("mulled_channels", DEFAULT_CHANNELS),
             "hash_func": self.hash_func,
             "command": "build-and-test",
+            "namespace": "local",
             "singularity": True,
             "singularity_image_dir": self.cache_directory.path,
             "use_mamba": True,