fix(image-builder): Use SDK version that matches PyFunc servers (#499)

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**What this PR does / why we need it**:
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the problem you're trying to solve. --->

Users may sometimes add an explicit dependency on `merlin-sdk` whose
version may not be compatible with the Pyfunc Real-time / Batch server.
This PR adds a step to the image building such that, the local copy of
the SDK in the model server will be re-installed into the model
environment, in the final step - this way, the server and SDK will
always be in sync.

**Which issue(s) this PR fixes**:
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Usage: `Fixes #<issue number>`, or `Fixes (paste link of issue)`.
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Handles cases where a user specified dependency on `merlin-sdk` in their
model could lead to a mismatch on the Pyfunc server.

**Does this PR introduce a user-facing change?**:
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```release-note
Force an SDK version that matches PyFunc servers during image building
```

**Checklist**

- [ ] Added unit test, integration, and/or e2e tests
- [ ] Tested locally
- [ ] Updated documentation
- [ ] Update Swagger spec if the PR introduce API changes
- [ ] Regenerated Golang and Python client if the PR introduce API
changes

python/batch-predictor/docker/app.Dockerfile

@@ -27,4 +27,5 @@ RUN /bin/bash -c ". activate ${CONDA_ENVIRONMENT} && \
     sed -i 's/mlflow[><=]\{0,1\}.*$/mlflow==1.26.1/g' ${HOME}/model/conda.yaml && \
     sed -i '/merlin-sdk/d' ${HOME}/model/conda.yaml && \
     conda env update --name ${CONDA_ENVIRONMENT} --file ${HOME}/model/conda.yaml && \
+    pip install ${SDK_PATH} && \
     python ${HOME}/merlin-spark-app/main.py --dry-run-model ${HOME}/model"

python/pyfunc-server/docker/Dockerfile

@@ -27,6 +27,7 @@ RUN /bin/bash -c ". activate merlin-model && \
     sed -i 's/mlflow[><=]\{0,1\}.*$/mlflow==1.26.1/g' model/conda.yaml && \
     sed -i '/merlin-sdk/d' model/conda.yaml && \
     conda env update --name merlin-model --file model/conda.yaml && \
+    pip install ${SDK_PATH} && \
     python -m pyfuncserver --model_dir model --dry_run"
 
 CMD ["/bin/bash", "./run.sh"]