fix: replace deprecated asyncio.get_event_loop() with modern approach

[Abdeldjalil-H]

Replace deprecated get_event_loop() with get_running_loop() and fallback to new_event_loop() to fix the "no current event loop" warning in Python 3.10+ #1824

Description

This PR updates the event loop handling in the test suite by replacing the deprecated asyncio.get_event_loop() with the modern approach using get_running_loop() with a fallback to new_event_loop(). The change specifically targets the code in /tortoise/contrib/test/__init__.py.

Motivation and Context

Since Python 3.10, using asyncio.get_event_loop() triggers a deprecation warning:
DeprecationWarning: There is no current event loop

This change modernizes the code to use the recommended approach for handling event loops, eliminating the deprecation warning while maintaining functionality.

How Has This Been Tested?

Running tests

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added the changelog accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codspeed-hq]

CodSpeed Performance Report

Merging #1865 will not alter performance

_{Comparing Abdeldjalil-H:fix/event-loop-warning (0a7fffd) with develop (960b1c1)}

Summary

✅ 12 untouched benchmarks

[coveralls]

Pull Request Test Coverage Report for Build 13026698161

Details

• 6 of 6 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.003%) to 89.236%

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Totals
Change from base Build 13012319268:	-0.003%
Covered Lines:	6493
Relevant Lines:	7092

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💛 - Coveralls

[waketzheng]

Use 0.24.1 (unreleased) instead of 0.24.1

[henadzit]

@Abdeldjalil-H, can you please merge your changes with develop? We added the 0.25.0 version to the CHANGELOG by mistake, can you please move the change from there under 0.24.1? Thanks!