[DRAFT] Update group_texts in run_clm.py
Author: spanglies
Pull request: yes

Had to make this change to prevent error's when fine-tuning on SageMaker. Without this change, there would be text groups that were too short.

# What does this PR do?
I made a small change to run_clm.py that fixed an error I received on amazon sagemaker during finetuning.
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