Fix island chat using team chat log setting and prefix

[Copilot]

ChatListener.islandChat() was using isLogTeamChats() and logging [Team Chat Log], despite Settings already having a dedicated isLogIslandChats() field backed by island-chat.log in config. The island-chat logging tests reflected this bug, stubbing the wrong setting and asserting the wrong prefix.

Changes

• ChatListener.java: islandChat() now calls isLogIslandChats() and logs [Island Chat Log]
• ChatListenerTest.java: Island-chat logging tests updated to stub isLogIslandChats() and assert [Island Chat Log] prefix

// Before
if (addon.getSettings().isLogTeamChats()) {
    addon.log("[Team Chat Log] " + player.getName() + ": " + message);
}

// After
if (addon.getSettings().isLogIslandChats()) {
    addon.log("[Island Chat Log] " + player.getName() + ": " + message);
}