bug: login_hint always sent in oauth init

Signed-off-by: Nick Gerakines <[e-mail]>

crates/atproto-oauth-aip/src/workflow.rs

···
 pub async fn oauth_init(
     http_client: &reqwest::Client,
     oauth_client: &OAuthClient,
-    handle: Option<&str>,
+    login_hint: Option<&str>,
     authorization_server: &AuthorizationServer,
     oauth_request_state: &OAuthRequestState,
 ) -> Result<ParResponse> {
···
         ("scope", scope),
         ("state", oauth_request_state.state.as_str()),
     ];
-    if let Some(value) = handle {
+    if let Some(value) = login_hint {
         params.push(("login_hint", value));
     }
 

crates/atproto-oauth/src/workflow.rs

···
     http_client: &reqwest::Client,
     oauth_client: &OAuthClient,
     dpop_key_data: &KeyData,
-    handle: &str,
+    login_hint: Option<&str>,
     authorization_server: &AuthorizationServer,
     oauth_request_state: &OAuthRequestState,
 ) -> Result<ParResponse, OAuthClientError> {
···
         .with(ChainMiddleware::new(dpop_retry.clone()))
         .build();
 
-    let params = [
+    let mut params = vec![
         ("response_type", "code"),
         ("code_challenge", &oauth_request_state.code_challenge),
         ("code_challenge_method", "S256"),
···
         ("state", oauth_request_state.state.as_str()),
         ("redirect_uri", oauth_client.redirect_uri.as_str()),
         ("scope", scope),
-        ("login_hint", handle),
         (
             "client_assertion_type",
             "urn:ietf:params:oauth:client-assertion-type:jwt-bearer",
         ),
         ("client_assertion", client_assertion_token.as_str()),
     ];
+    if let Some(value) = login_hint {
+        params.push(("login_hint", value));
+    }
 
     let response = dpop_retry_client
         .post(par_url)