fix: Showing "Browse subgenres" folder coming from "Previous page"

[Falke-Design]

Check if this PR fulfills these requirements:

• My changes respect the Kodi add-on development rules
• I have read the CONTRIBUTING document.
• I made sure there wasn't another Pull Request opened for the same update/change
• I have successfully tested my changes locally

Types of changes

• New feature (non-breaking change which adds functionality)
• Feature change (non-breaking change which changes behaviour of an existing functionality)
• Improvement (non-breaking change which improves functionality)
• Bug fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to change)
• Refactor (non-breaking performance or readability improvements)

Description

Fixes: #1660

"Browse Subgenres" folder was not available if the first page was opened over "Previous page".
The subgenres_id was not passed to the next page, so it was not possible to re-create the "Subgenres" folder after clicking "Previous page".
Now the subgenres_id is always passed but the folder "Browse Subgenres" is only on the first page visible. The first page is detected over 'previous_start' not in video_list.perpetual_range_selector

In case of Feature change / Breaking change:

Describe the current behavior

Describe the new behavior

Screenshots (if appropriate):

Before:

[CastagnaIT]

has sense, thank you