Kobo: Minor simplification after koreader#12616 (koreader#12629)

The only codepath that sets pending_connection to true in NetworkManager calls turnOnWifi right after, so we can't really ever see pending_connection w/o isWifiOn being also true ;).

frontend/device/kobo/device.lua

@@ -1347,7 +1347,7 @@ function Kobo:suspend()
     -- Murder Wi-Fi (again, c.f., `Device:onPowerEvent`) if NetworkMgr is attempting to connect or currently connected...
     -- (Most likely because of a rerunWhenOnline in a Suspend handler)
     local network_mgr = require("ui/network/manager")
-    if network_mgr:isWifiOn() or network_mgr.pending_connection then
+    if network_mgr:isWifiOn() then
         logger.info("Kobo suspend: had to kill Wi-Fi")
         network_mgr:disableWifi()
     end