Force usage of best index for conversation query.

app/src/main/java/org/thoughtcrime/securesms/database/MessageTable.kt

@@ -4577,7 +4577,7 @@ open class MessageTable(context: Context?, databaseHelper: SignalDatabase) : Dat
 
     return readableDatabase
       .select(*MMS_PROJECTION)
-      .from(TABLE_NAME)
+      .from("$TABLE_NAME INDEXED BY $INDEX_THREAD_STORY_SCHEDULED_DATE_LATEST_REVISION_ID")
       .where("$THREAD_ID = ? AND $STORY_TYPE = ? AND $PARENT_STORY_ID <= ? AND $SCHEDULED_DATE = ? AND $LATEST_REVISION_ID IS NULL", threadId, 0, 0, -1)
       .orderBy("$DATE_RECEIVED DESC")
       .limit(limitStr)