use 'Either InvalidUrlException' as a base monad for requestFromURI

  Again... errors from 'requestFromURI' are thrown via 'MonadThrow', which, in the case of 'ExceptT' throws in the base monad, which is IO in this case.

lib/core/src/Cardano/Pool/Metadata.hs

@@ -169,7 +169,7 @@ fetchFromRemote tr builders manager url hash = runExceptTLog $ do
 
     getChunk :: URI -> ExceptT String IO (Maybe ByteString)
     getChunk uri = do
-        req <- requestFromURI uri
+        req <- withExceptT show $ except $ requestFromURI uri
         liftIO $ traceWith tr $ MsgFetchPoolMetadata hash uri
         ExceptT
             $ handle fromIOException