reduced channel name min length to 2 (#5570)

model/channel.go

@@ -15,7 +15,7 @@ const (
 	CHANNEL_DIRECT                 = "D"
 	DEFAULT_CHANNEL                = "town-square"
 	CHANNEL_DISPLAY_NAME_MAX_RUNES = 64
-	CHANNEL_NAME_MIN_LENGTH        = 3
+	CHANNEL_NAME_MIN_LENGTH        = 2
 	CHANNEL_NAME_MAX_LENGTH        = 64
 	CHANNEL_HEADER_MAX_RUNES       = 1024
 	CHANNEL_PURPOSE_MAX_RUNES      = 250