Making prompts clear for low parameter models.

[PranavPuranik]

Description

Current prompt for returning json output -

Do not return anything except the JSON format.

It has 2 negations and it didn't work for meta-llama/Meta-Llama-3.1-70B-Instruct

A better prompt that worked -

Only return the json format, do not add ``` around the json in the response. Start directly with {{ so I can load the response in json.loads() function. 

This worked for the model.

Fixes #1885 #1854

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (does not change functionality, e.g. code style improvements, linting)
• Documentation update

How Has This Been Tested?

This change requires more testing, I don't have access to all models you support.

I tested on the example using meta-llama/Meta-Llama-3.1-70B-Instruct and gpt 4o

• Unit Test
• Test Script (please provide)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• 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
• I have checked my code and corrected any misspellings

Maintainer Checklist

• closes #xxxx (Replace xxxx with the GitHub issue number)
• Made sure Checks passed