handle giveKeyChainTriggeredMessage with ChainStage = -1

e.g. for railjack build quest, the initial inbox message is sent like this. no 'm' needs to be set to true for it.

src/services/questService.ts

@@ -83,7 +83,6 @@ export const updateQuestStage = (
             `Quest stage index mismatch: stage is ${ChainStage} but array size is ${quest.Progress.length}`
         );
     }
-    // Note that the client may use index 0 as well, e.g. for rising tide's initial inbox message. 'm' is not tracked for it.
     if (ChainStage >= 0) {
         const questStage = quest.Progress[ChainStage]; // guaranteed in-bounds now