Fix additional level of nesting that can not be flattened using serde

Unfortunately, flattening enums with serde is blocked on
serde-rs/serde#1402.

Signed-off-by: Pablo Sichert <mail@pablosichert.com>

src/codecs/encoding/mod.rs

@@ -95,17 +95,17 @@ impl tokio_util::codec::Encoder<()> for Framer {
 #[serde(tag = "codec", rename_all = "snake_case")]
 pub enum SerializerConfig {
     /// Configures the `JsonSerializer`.
-    Json(JsonSerializerConfig),
+    Json,
     /// Configures the `RawMessageSerializer`.
-    RawMessage(RawMessageSerializerConfig),
+    RawMessage,
 }
 
 impl SerializerConfig {
     /// Build the `Serializer` from this configuration.
     pub const fn build(&self) -> Serializer {
         match self {
-            SerializerConfig::Json(config) => Serializer::Json(config.build()),
-            SerializerConfig::RawMessage(config) => Serializer::RawMessage(config.build()),
+            SerializerConfig::Json => Serializer::Json(JsonSerializer::new()),
+            SerializerConfig::RawMessage => Serializer::RawMessage(RawMessageSerializer::new()),
         }
     }
 }

src/sinks/util/encoding/adapter.rs

@@ -281,7 +281,7 @@ mod tests {
             EncodingConfigAdapter::LegacyEncodingConfig(_) => panic!(),
         };
 
-        assert!(matches!(encoding, SerializerConfig::RawMessage(_)));
+        assert!(matches!(encoding, SerializerConfig::RawMessage));
     }
 
     #[test]