android: fix missing header and remove extra import

Updates #cleanup

Author: kari-ts

android/src/main/java/com/tailscale/ipn/ui/view/ExitNodePicker.kt

@@ -3,7 +3,6 @@
 
 package com.tailscale.ipn.ui.view
 
-import android.os.Build
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Row