don't convert URL to lower ascii, fixes #3756 (#3757)

beacon_chain/eth1/eth1_monitor.nim

@@ -267,11 +267,8 @@ proc fixupWeb3Urls*(web3Url: var string) =
           normalizedUrl.startsWith("http://") or
           normalizedUrl.startsWith("wss://") or
           normalizedUrl.startsWith("ws://")):
-    normalizedUrl = "ws://" & normalizedUrl
     warn "The Web3 URL does not specify a protocol. Assuming a WebSocket server", web3Url
-
-  # We do this at the end in order to allow the warning above to print the original value
-  web3Url = normalizedUrl
+    web3Url = "ws://" & web3Url
 
 template toGaugeValue(x: Quantity): int64 =
   toGaugeValue(distinctBase x)