fix(android): ProGuard keep getId (tauri-apps#1721)

closes tauri-apps/tauri#15311

Author: lucasfernog

.changes/keep-get-id.md

@@ -0,0 +1,5 @@
+---
+"wry": patch
+---
+
+Tweak ProGuard rules to keep the getId required activity method.

src/android/kotlin/proguard-wry.pro

@@ -11,6 +11,7 @@
 
   void setWebView({{package-unescaped}}.RustWebView);
   java.lang.Class getAppClass(...);
+  int getId();
   java.lang.String getVersion();
   int startActivity(...);
 }