Handle case where num_query_groups is set to null for LoRA config setup
@cuichenx / @ericharper, can you review this one?  Thanks! Merging this because it's only failing on a problematic test which is being commented out in #9085 
# What does this PR do ?

Currently, LoRA setup uses either the num_query_groups setting (if set) or the num_attention_heads setting, if not.  However, if num_query_groups is set explicitly to null, this line evaluates to None instead of the num_attention_heads value, resulting in `TypeError: unsupported operand type(s) for *: 'int' and 'NoneType'`.  This tiny change just adds an additional check to account for this situation.

**Collection**: nlp

# Changelog 
- Adds an additional check to LoRA config setup, setting num_query_groups to num_attention_heads if None.

# Usage
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```python
# Add a code snippet demonstrating how to use this 
```

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# Additional Information
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