Use GetDynPath for getPlayingFile

[angelblue05]

Description

Update Player getPlayingFile() to use the new GetDynPath() instead of GetPath().
Forum post: https://forum.kodi.tv/showthread.php?tid=331523

Motivation and Context

Fix broken behavior due to new file path changes in Leia.

How Has This Been Tested?

Compiled Kodi on Windows x64.

Types of change

• Bug fix (non-breaking change which fixes an issue)
• Improvement (non-breaking change which improves existing functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the Code guidelines of this project
• My change requires a change to the documentation, either Doxygen or wiki
• I have updated the documentation accordingly
• I have read the CONTRIBUTING document
• I have added tests to cover my change
• All new and existing tests passed