Improve Makefile Compatibility and Update Model Version

[SuchanaNag002]

This pull request introduces several key improvements to the Makefile for enhanced compatibility and functionality and updates the model version used in the codebase to ensure continued functionality with the OpenAI API.

1)Enhanced Makefile Compatibility:
1.1)Improved Poetry Detection:
Modified the ensure-poetry target to use a more portable and robust method for checking Poetry installation. The new check uses:
@if [ -z "$$(which poetry)" ]; then ...
This change improves compatibility with Unix-like shells and addresses issues with command substitution.

1.2)Correct Use of Deferred Command Execution:
Adjusted command substitution from $(...) to $$(...) to ensure commands are evaluated at runtime, aligning with Makefile best practices and avoiding premature evaluation.

1.3)Informative Error Messaging:
Maintained clear error messages to guide users in activating the correct Conda environment if Poetry is not found, providing better assistance during setup:
echo "Did you activate the outer conda environment? Run: conda activate llm-math-education";

1.4)General Cleanup:
Ensured consistent use of tabs for indentation, following Makefile syntax requirements for accurate command parsing.

2)Model Version Update:
2.1)Updated Deprecated Model Version:
Changed the model parameter from model="gpt-3.5-turbo-0613" to model="gpt-3.5-turbo-0125" due to deprecation of the older model.
This update ensures compatibility with the latest OpenAI API and prevents potential disruptions in functionality.

3)Testing and Verification
Compatibility: Tested across different operating systems to ensure the Makefile functions correctly and the updated model is supported by the OpenAI API.
Developer Onboarding: Verified that the changes reduce setup time and minimize potential errors during the environment setup.
API Functionality: Confirmed that the updated model parameter does not impact existing functionality and is aligned with the latest API updates.