[fix][1760] Added fix for the missing `context` key issue in dolly!

[pytholic]

What is the type of this PR?

• [ ] Refactor (refactored code that neither fixes a bug nor adds a feature)
• [ ] Feature (non-breaking change which adds functionality)
• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Test (including new or correcting previous tests)
• [ ] Style (changes to code formatting and styling)
• [ ] Optimization (performance improvements)
• [ ] Documentation Update (updates to the documentation (i.e. README, comments, docstrings, etc.)
• [ ] Revert (reverts a previous commit)

Motivation and Context

To fix the issue where context key error was thrown in Dolly dataloader.

Modifications

The following changes were made in this PR.

• Update _transform in dolly.py
• Added a test for it
• Updated printing a bit

How Has This Been Tested?

I added the following test to simulate the original issue. The code has been tests on MacOS.

• tests/data/test_dolly.py::test_dolly_missing_keys

Previous behavior

After fixing

Checklist:

• [ ] My code follows the style guidelines of this project
• [x] I have performed a self-review of my code
• [x] I have commented on my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [ ] New and existing unit tests pass locally with my changes
• [ ] Any dependent changes have been merged and published in downstream modules

Notes

1. I noticed that some tests related to the tokenizer are failing. Note that these are not related to my updates (CC: @rasbt ).

2. I updated the printing logs a bit. The instruction was being printed twice which wasn't appealing. I have also added some newline characters. I applied it to only lora.py. If it is desirable, it can be applied to other scripts as well.

Before

After