Update Convert Temperature.py

[Om149]

Renamed functions to follow snake_case naming and better clarity.

Replaced global variables and nested conditions with modular pure functions for each conversion path.

Added input validation for temperature and conversion choices.

Removed unnecessary import of math module.

Used consistent formatting and meaningful function/variable names.

Improved user prompts for better UX.

PR Title

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Summary

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Description

The changes are as follows:

• Change 1
• Change 2

Checks

in the repository

• [ ] Made no changes that degrades the functioning of the repository
• [ ] Gave each commit a better title (unlike updated README.md)

in the PR

• [ ] Followed the format of the pull_request_template
• [ ] Made the Pull Request in a small level (for the creator's wellfare)
• [ ] Tested the changes you made

Thank You,

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