fix: install uv in 'run-task' image as well

`run-task` now has a feature where it will use `uv` to install pip
packages, so it makes sense to include `uv` here as well.

Note the Decision image uses `run-task` as a base, so this is *not*
removing `uv` from there.

taskcluster/docker/decision/Dockerfile

@@ -1,9 +1,6 @@
 FROM $DOCKER_IMAGE_PARENT
 LABEL maintainer="Release Engineering <[email protected]>"
 
-# %ARG UV_VERSION
-COPY --from=ghcr.io/astral-sh/uv:$UV_VERSION /uv /bin/uv
-
 ENV UV_PROJECT_ENVIRONMENT=/setup/taskgraph
 
 # %include src

taskcluster/docker/run-task/Dockerfile

@@ -16,5 +16,8 @@ ENV PATH=/builds/worker/bin:$PATH \
     SHELL=/bin/bash \
     HOME=/builds/worker
 
+# %ARG UV_VERSION
+COPY --from=ghcr.io/astral-sh/uv:$UV_VERSION /uv /bin/uv
+
 # Set a default command useful for debugging
 CMD ["/bin/bash", "--login"]