check for presence of transcript file before attempting to write to it

src/bot.js

@@ -173,6 +173,11 @@ class OcrccBot {
         timeZone: "America/New_York"
       });
       const filepath = this.localStorage.getItem(`${roomId}-transcript`)
+
+      if (!filepath) {
+        return logger.log("error", `NO TRANSCRIPT FILE FOR ROOM: ${roomId}`);
+      }
+
       const message = `${sender} [${time}]: ${content.body}\n`;
 
       fs.appendFileSync(filepath, message, "utf8");