Revert http client changes (#18892)

These proved to be too unstable. Will restore these changes once the issues have been fixed.

Release Notes:

- N/A

crates/reqwest_client/examples/client.rs

@@ -1,16 +0,0 @@
-use futures::AsyncReadExt as _;
-use http_client::AsyncBody;
-use http_client::HttpClient;
-use reqwest_client::ReqwestClient;
-
-#[tokio::main]
-async fn main() {
-    let resp = ReqwestClient::new()
-        .get("http://zed.dev", AsyncBody::empty(), true)
-        .await
-        .unwrap();
-
-    let mut body = String::new();
-    resp.into_body().read_to_string(&mut body).await.unwrap();
-    println!("{}", &body);
-}