fix: post apppassword bytes with headers expected json

crates/atproto-client/src/client.rs

···
     http_client: &reqwest::Client,
     app_auth: &AppPasswordAuth,
     url: &str,
-    record: serde_json::Value,
+    payload: Bytes,
     additional_headers: &HeaderMap,
 ) -> Result<Bytes> {
     let mut headers = additional_headers.clone();
···
     let http_response = http_client
         .post(url)
         .headers(headers)
-        .json(&record)
+        .body(payload)
         .send()
-        .instrument(tracing::info_span!("get_apppassword_bytes_with_headers", url = %url))
+        .instrument(tracing::info_span!("post_apppassword_bytes_with_headers", url = %url))
         .await
         .map_err(|error| ClientError::HttpRequestFailed {
             url: url.to_string(),