Explicitly set a user for the wpa_supplicant service

Otherwise the service fails to be registered.

Bug: 276813155
Test: `start wpa_supplicant`
Change-Id: I9bd44593a9afd3c6a28bc8ddba365589f729ab2d
diff --git a/wpa_supplicant/aidl/android.hardware.wifi.supplicant-service.rc b/wpa_supplicant/aidl/android.hardware.wifi.supplicant-service.rc
index 3275e36..807d2d3 100644
--- a/wpa_supplicant/aidl/android.hardware.wifi.supplicant-service.rc
+++ b/wpa_supplicant/aidl/android.hardware.wifi.supplicant-service.rc
@@ -8,5 +8,6 @@
 	interface aidl android.hardware.wifi.supplicant.ISupplicant/default
 	class main
 	socket wpa_wlan0 dgram 660 wifi wifi
+	user root
 	disabled
 	oneshot