Temporary Solution for Segmentation Fault During Evaluation

[KumoLiu]

Fixes #164

Description

Workaround for #164

Move openpi related import after initialize SimulationApp

[KumoLiu]

By moving the import policy to after the simulation app runs, we are able to receive more detailed error messages.

related to：boto/boto3#4399

Traceback (most recent call last):
  File "/home/yunliu/Workspace/Code/i4h-workflows/workflows/robotic_ultrasound/scripts/simulation/imitation_learning/pi0_policy/eval.py", line 68, in <module>
    from policy_runner.pi0.runners import PI0PolicyRunner
  File "/home/yunliu/Workspace/Code/i4h-workflows/workflows/robotic_ultrasound/scripts/policy_runner/pi0/runners.py", line 17, in <module>
    from openpi.policies import policy_config
  File "/home/yunliu/Workspace/Code/i4h-workflows/third_party/openpi/src/openpi/policies/policy_config.py", line 10, in <module>
    import openpi.policies.policy as _policy
  File "/home/yunliu/Workspace/Code/i4h-workflows/third_party/openpi/src/openpi/policies/policy.py", line 14, in <module>
    from openpi import transforms as _transforms
  File "/home/yunliu/Workspace/Code/i4h-workflows/third_party/openpi/src/openpi/transforms.py", line 11, in <module>
    from openpi.models import tokenizer as _tokenizer
  File "/home/yunliu/Workspace/Code/i4h-workflows/third_party/openpi/src/openpi/models/tokenizer.py", line 7, in <module>
    import openpi.shared.download as download
  File "/home/yunliu/Workspace/Code/i4h-workflows/third_party/openpi/src/openpi/shared/download.py", line 14, in <module>
    import boto3.s3.transfer as s3_transfer
  File "/home/yunliu/anaconda3/envs/i4h-test/lib/python3.10/site-packages/boto3/s3/transfer.py", line 135, in <module>
    from s3transfer.futures import NonThreadedExecutor
  File "/home/yunliu/anaconda3/envs/i4h-test/lib/python3.10/site-packages/s3transfer/futures.py", line 22, in <module>
    from s3transfer.utils import FunctionContainer, TaskSemaphore
  File "/home/yunliu/anaconda3/envs/i4h-test/lib/python3.10/site-packages/s3transfer/utils.py", line 29, in <module>
    from botocore.httpchecksum import DEFAULT_CHECKSUM_ALGORITHM, AwsChunkedWrapper
ImportError: cannot import name 'DEFAULT_CHECKSUM_ALGORITHM' from 'botocore.httpchecksum' (/home/yunliu/anaconda3/envs/i4h-test/lib/python3.10/site-packages/isaacsim/extscache/omni.kit.pip_archive-0.0.0+d02c707b.lx64.cp310/pip_prebundle/botocore/httpchecksum.py)

[Nic-Ma]

/build