GlobalSearchScreen: Add unique key (#8693)

Avoids crash when an old screen is being replaced by a new one

app/src/main/java/eu/kanade/tachiyomi/ui/browse/source/globalsearch/GlobalSearchScreen.kt

@@ -5,6 +5,7 @@ import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import cafe.adriel.voyager.core.model.rememberScreenModel
 import cafe.adriel.voyager.core.screen.Screen
+import cafe.adriel.voyager.core.screen.uniqueScreenKey
 import cafe.adriel.voyager.navigator.LocalNavigator
 import cafe.adriel.voyager.navigator.currentOrThrow
 import eu.kanade.presentation.browse.GlobalSearchScreen
@@ -16,6 +17,8 @@ class GlobalSearchScreen(
     val extensionFilter: String = "",
 ) : Screen {
 
+    override val key = uniqueScreenKey
+
     @Composable
     override fun Content() {
         val navigator = LocalNavigator.currentOrThrow