Do not log in aws_credentials_provider

Currently we log errors even if one of the credentials are
available, which is verbose and often confusing.

Given we already log or fail when no credentials are available,
let's remove the logging from individual providers.

src/aws_credentials_provider.erl

@@ -78,7 +78,6 @@ evaluate_providers([ Provider | Providers ], Options, Errors) ->
             String = "Provider ~p reports ~p",
             Args = [Provider, Error],
             Metadata = #{domain => [aws_credentials]},
-            aws_credentials:log_error(String, Args, Metadata),
             evaluate_providers(Providers, Options, [{String, Args, Metadata} | Errors]);
         {ok, Credentials, Expiration} ->
             {ok, Credentials, Expiration}