[wifi] Avoid BDK 3.0.78 wifi_event_sta_disconnected_t collision on BK72xx

BDK 3.0.78 (required by LibreTiny for BK7238 support, see
libretiny-eu/libretiny#360) declares wifi_event_sta_disconnected_t in
wlan_defs_pub.h, which collides with the identically named typedef in
LibreTiny's Arduino WiFi API (WiFiEvents.h). Rename the BDK version
across the include so both headers can coexist. ESPHome only uses
bk_wlan_get_link_status from this header and doesn't reference the
renamed type.

The rename is a no-op on BDK 3.0.33 (BK7231T/N) since that version
doesn't declare the typedef.

esphome/components/wifi/wifi_component_libretiny.cpp

@@ -12,7 +12,12 @@
 
 #ifdef USE_BK72XX
 extern "C" {
+// BDK 3.0.78 (required for BK7238) redeclares wifi_event_sta_disconnected_t,
+// which LibreTiny's Arduino WiFi API already defines. ESPHome doesn't use the
+// BDK version, so rename it across this include to avoid the collision.
+#define wifi_event_sta_disconnected_t bdk_wifi_event_sta_disconnected_t
 #include <wlan_ui_pub.h>
+#undef wifi_event_sta_disconnected_t
 }
 #endif