explicit type imports to help robustness of isinstance check for images

[mathematicalmichael]

I still don't entirely have an explanation for this, but when I ran eden within docker, the client script that was working fine locally started running into the following error when the IP was changed to the container's address:

File "/home/eden/.local/lib/python3.10/site-packages/eden/datatypes.py", line 33, in __init__
    self.data = encode(image)
  File "/home/eden/.local/lib/python3.10/site-packages/eden/image_utils.py", line 41, in encode
    or isinstance(
TypeError: isinstance() arg 2 must be a type, a tuple of types, or a union

For context, eden-python was installed with pip in the docker image. When I sent a request to the container (from a client script running locally), I was getting "failed" statuses, and the logs of the container contained the error above printed to stdout (I set logfile=None in my server.py).

I added the proposed modified image_utils.py file into the build as a test for this change and consistently started getting "complete" statuses (tested this many times, seems to be reproducible behavior).

COPY image_utils.py /home/eden/.local/lib/python3.10/site-packages/eden/image_utils.py

Full Dockerfile for context (server.py is the not_so_minimal example...)

FROM pytorch/pytorch:1.13.1-cuda11.6-cudnn8-runtime

RUN apt-get update && apt-get install -y \
    libgl1-mesa-glx \
    libglib2.0-0 \
    && rm -rf /var/lib/apt/lists/*

# for gitpython (TODO: can we remove this requirement somehow? Or work with it as a design constraint?)
RUN apt-get update && apt-get install -y \
    git \
    && rm -rf /var/lib/apt/lists/*

WORKDIR /app
RUN useradd -ms /bin/bash eden
RUN chown eden:eden /app

USER eden
ENV PATH="/home/eden/.local/bin:${PATH}"
RUN pip install eden-python
COPY server.py .
# attempted bugfix
COPY image_utils.py /home/eden/.local/lib/python3.10/site-packages/eden/image_utils.py

EXPOSE 5656
# hack around gitpython until better solution (PR?) presents itself
RUN git init .
RUN git config --global user.email "none@site.com"
RUN git config --global user.name "eden-service-user"
# add fake remote upstream bc the above gets you past git.exc exception only to hit AttributeError for a missing remote
RUN git remote add origin https://git.clfx.cc/mm/eden-app.git
RUN git add server.py
RUN git commit -am "initial commit"

CMD ["python", "server.py"]