docs(ffi): add breaking change entry for Client::url_for_oidc

Signed-off-by: fl0lli <github@fl0lli.de>

Author: fl0lli

bindings/matrix-sdk-ffi/CHANGELOG.md

@@ -11,6 +11,8 @@ All notable changes to this project will be documented in this file.
 - `ClientBuilder::build_with_qr_code` has been removed. Instead, the Client should be built by passing
   `QrCodeData::server_name` to `ClientBuilder::server_name_or_homeserver_url`, after which QR login can be performed by
   calling `Client::login_with_qr_code`. ([#5388](https://github.com/matrix-org/matrix-rust-sdk/pull/5388))
+- `Client::url_for_oidc` now allows passing an optional existing device id from a previous login call.
+  ([#5394](https://github.com/matrix-org/matrix-rust-sdk/pull/5394))
 
 ## [0.13.0] - 2025-07-10