Fix sceNpGetAccountId

Further hardware testing shows that these always write 0 to account_id when failing.

src/core/libraries/np_manager/np_manager.cpp

@@ -941,6 +941,7 @@ int PS4_SYSV_ABI sceNpGetAccountId(OrbisNpOnlineId* online_id, u64* account_id)
     if (online_id == nullptr || account_id == nullptr) {
         return ORBIS_NP_ERROR_INVALID_ARGUMENT;
     }
+    *account_id = 0;
     return ORBIS_NP_ERROR_SIGNED_OUT;
 }
 
@@ -949,6 +950,7 @@ int PS4_SYSV_ABI sceNpGetAccountIdA(OrbisUserServiceUserId user_id, u64* account
     if (account_id == nullptr) {
         return ORBIS_NP_ERROR_INVALID_ARGUMENT;
     }
+    *account_id = 0;
     return ORBIS_NP_ERROR_SIGNED_OUT;
 }