fix: fix missing control paths issue

Fix regression issue in commit: 5e8aca2

```
trime/app/src/main/jni/librime/src/rime/switches.cc:117:1: error: non-void function does not return a value in all control paths [-Werror,-Wreturn-type]
  }
  ^
  1 error generated.
```

We can add more compiler option in CI to avoid issue like this.

src/rime/switches.cc

@@ -114,6 +114,7 @@ Switches::SwitchOption Switches::Reset(const SwitchOption& current) {
       default_state,
     };
   }
+  return {};
 }
 
 Switches::SwitchOption Switches::FindRadioGroupOption(