Fix(spotify): Disable loadLyrics when disabled by config

[RayGGuzman]

Fixes an issue where Spotify lyrics logic executed even if explicitly disabled via configuration.

The core problem: SpotifySourceManager implements AudioLyricsManager, causing it to be called by the LavaLyrics fallback mechanism whenever a Spotify track was loaded, even if 'lyrics-sources: spotify: false'.

This unintended invocation of loadLyrics() triggered the required logic to obtain an Account Token (checking spDc or customTokenEndpoint). If this token source was misconfigured or unavailable, it resulted in persistent 'Connection refused' errors in the logs, despite the user only enabling Spotify for audio playback.

Implementation Details:

1. Guard Clause: Added a 'boolean lyricsEnabled' flag to SpotifySourceManager.
2. Logic Bypass: loadLyrics() now checks this flag and returns null immediately if disabled.
3. Plugin Update: LavaSrcPlugin.java now explicitly passes the value of lyricsSourcesConfig.isSpotify() to the SpotifySourceManager constructor, making lyrics functionality strictly opt-in.

[topi314]

are you on an old version of lavalyrics?
because that behavior got changed some time ago
https://github.com/topi314/LavaLyrics/blob/7d6007703735e07f1182cc41e71cdf60f18f5dfe/main/src/main/java/com/github/topi314/lavalyrics/LyricsManager.java#L67