Add ability to retrieve playlist items by libtype

[JonnyWong16]

Description

Add ability to retrieve playlist items by libtype.

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated the docstring for new or existing methods
• I have added tests when applicable

[Copilot]

Pull request overview

Adds support for filtering playlist items by library type (libtype) when retrieving items from a playlist.

Changes:

• Extend Playlist.items() to accept an optional libtype filter and pass type=<searchType> to the /playlists/<id>/items query.
• Refactor item-fetching logic into a helper and keep the unfiltered result cached via @cached_data_property.
• Add a new test validating items(libtype=...) behavior for show/season/episode.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
plexapi/playlist.py	Adds optional libtype filtering when fetching playlist items (via type query param) while preserving cached unfiltered results.
tests/test_playlist.py	Renames the playlist items test and adds coverage for retrieving playlist items filtered by libtype.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

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[Copilot]

playlist.delete() in the finally block can raise UnboundLocalError if plex.createPlaylist(...) fails before playlist is assigned. Initialize playlist = None before the try and guard the delete (e.g., if playlist: playlist.delete()).