Fix Django deprecation warnings and code cleanup

[RajdeepKushwaha5]

Overview

This PR addresses deprecation warnings in the Django application and performs minor code cleanup to improve maintainability and future compatibility.

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Changes Made

1. Fixed pythonjsonlogger Import Deprecation

File: settings.py

• Change: Updated the logging formatter import from
  "pythonjsonlogger.jsonlogger.JsonFormatter" → "pythonjsonlogger.json.JsonFormatter"
• Reason: The jsonlogger module has been moved to json in newer versions of python-json-logger, causing deprecation warnings.
• Impact: Eliminates deprecation warning in logs without affecting functionality.

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2. Fixed Django 6.0 URLField Deprecation Warning

File: settings.py

• Change: Added FORMS_URLFIELD_ASSUME_HTTPS = True setting
• Reason: Django 6.0 will change the default scheme for URLField from 'http' to 'https'.
  This setting silences the warning and opts into the new behavior.
• Impact: Prevents warnings in tests and forms, ensuring compatibility with future Django versions.

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3. Removed Unused Imports

Files:

• settings.py: Removed from django.templatetags.static import static

• homework.py: Removed from courses.validators.validating_json_field import ValidatingJSONField

• Reason: These imports were not used in the code, leading to linting warnings and potential confusion.

• Impact: Cleaner code, reduced import overhead, no functional changes.

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Testing

• Test Suite: All 178 tests pass successfully
• Coverage: No regressions in existing functionality
• Warnings: Reduced deprecation warnings (pythonjsonlogger warning eliminated)
• Manual Testing: Verified that the application starts and core features work as expected

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Impact Assessment

Area	Impact
Breaking Changes	None
Performance	No impact
Security	No impact
User Experience	No impact
Database	No migrations required

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Motivation

These changes improve code quality and prepare the codebase for Django 6.0 by addressing deprecation warnings that would become errors in future versions.
The cleanup also enhances maintainability by removing unused code.

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Checklist

• Tests pass
• No breaking changes
• Code follows project style guidelines
• Documentation updated (not applicable)
• Reviewed for security implications

[alexeygrigorev]

Can you remove formatting edits? it's hard to understand which changes are important and which are just formatting