fix(android): adjust Android plugin command exception to use e.message (#6831)

Author: lucasfernog

.changes/android-plugin-command-exception.md

@@ -0,0 +1,5 @@
+---
+"tauri": patch
+---
+
+Adjust Android plugin exception error.

core/tauri/mobile/android/src/main/java/app/tauri/plugin/PluginManager.kt

@@ -119,7 +119,7 @@ class PluginManager(val activity: AppCompatActivity) {
         plugins[pluginId]?.invoke(invoke)
       }
     } catch (e: Exception) {
-      invoke.reject(e.toString())
+      invoke.reject(e.message)
     }
   }