feat(creator): 팬Talk 쓰기 화면을 연결한다

SodaLive/Sources/App/AppStep.swift

@@ -127,6 +127,14 @@ enum AppStep {
     case creatorCommunityWrite(onSuccess: () -> Void)
     
     case creatorCommunityModify(postId: Int, onSuccess: () -> Void)
+
+    case creatorChannelFanTalkWrite(
+        creatorId: Int,
+        mode: CreatorChannelFanTalkWriteViewModel.Mode,
+        fanTalkId: Int?,
+        initialContent: String,
+        onSuccess: () -> Void
+    )
     
     case canCoupon(refresh: () -> Void)