Remove file with invalid Windows colon from tracking

[tamas2006]

Description

Removes the audio file containing a colon (:) in the filename (2022-11-25_NGC 6744: Extragalactic Close-Up.mp3), which previously blocked Windows users from cloning or checking out the repository due to operating system file restrictions.

Fixes #456

Type of change

• Bug fix (non-breaking change which fixes an issue)

Project

Your Project Name:
Not applicable

Short Description:
Not applicable (this is a repository bug fix, not a new project addition).

Checklist:

Please tick all the boxes that are fulfilled by your Pull Request.

• I have named my files and folder, according to this project's guidelines.
• My code follows the style guidelines of this project.
• I have commented on my code, particularly in hard-to-understand areas.
• I have created a helpful and easy to understand README.md, according to the given README_TEMPLATE.
• My changes do not produce any warnings.