Small fix cleanups

[CastagnaIT]

Description

For the commit relative to EXT-X-DISCONTINUITY i found following HLS manifest
manifest_1690801308_child-video.txt (only video stream)
that set discontinuity tag on the top of all segments, playin this currently print Segment at position 0 not found error that its better change it

now it is not clear to me why has been added on top of all segments, fwik discontinuity should have at least one segment, so i changed error to debug logging

How has this been tested?

Screenshots (if appropriate):

Types of change

• Bug fix (non-breaking change which fixes an issue)
• Clean up (non-breaking change which removes non-working, unmaintained functionality)
• Improvement (non-breaking change which improves existing functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that will cause existing functionality to change)
• Cosmetic change (non-breaking change that doesn't touch code)
• None of the above (please explain below)

Checklist:

• I have read the Contributing document
• My code follows the Code Guidelines of this project
• My change requires a change to the Wiki documentation
• I have updated the documentation accordingly