Use serde_as DisplayFromStr everywhere (#4103)

We used `display_serialize` previously, but it works only for Serialize.
`DisplayFromStr` does the same, but also works for Deserialize.

libs/utils/src/http/json.rs

@@ -1,9 +1,7 @@
-use std::fmt::Display;
-
 use anyhow::Context;
 use bytes::Buf;
 use hyper::{header, Body, Request, Response, StatusCode};
-use serde::{Deserialize, Serialize, Serializer};
+use serde::{Deserialize, Serialize};
 
 use super::error::ApiError;
 
@@ -33,12 +31,3 @@ pub fn json_response<T: Serialize>(
         .map_err(|e| ApiError::InternalServerError(e.into()))?;
     Ok(response)
 }
-
-/// Serialize through Display trait.
-pub fn display_serialize<S, F>(z: &F, s: S) -> Result<S::Ok, S::Error>
-where
-    S: Serializer,
-    F: Display,
-{
-    s.serialize_str(&format!("{}", z))
-}