refactor(relay): align max log level at compile time to other bins

trace were enabled on release build since the relay was considered as
unstable at start, since it has been stable for some time now we can
align it to other bin crate (debug: all level enabled, release: max
level debug).

Author: Alenar

mithril-relay/Cargo.toml

@@ -44,7 +44,7 @@ serde = { workspace = true }
 serde_json = { workspace = true }
 slog = { workspace = true, features = [
     "max_level_trace",
-    "release_max_level_trace",
+    "release_max_level_debug",
 ] }
 slog-async = { workspace = true }
 slog-bunyan = { workspace = true }