Adding 1s time gap between back-to-back calling setDataThrottling API

Modem has restriction that it can not process back-to-back thermal actions.
Adding 1s delay to prevent unexpected errors.

Bug: 181634712
Test: atest VtsHalRadioV1_6TargetTest -- --test-arg com.android.tradefed.testtype.GTest:native-test-flag:"--gtest_filter=*setDataThrottling/0_slot1"
Change-Id: I70a717cbc3a63d5b1abb4be9d3920d0ee3451b14
diff --git a/radio/1.6/vts/functional/radio_hidl_hal_api.cpp b/radio/1.6/vts/functional/radio_hidl_hal_api.cpp
index f343707..7c05984 100644
--- a/radio/1.6/vts/functional/radio_hidl_hal_api.cpp
+++ b/radio/1.6/vts/functional/radio_hidl_hal_api.cpp
@@ -433,6 +433,8 @@
                  ::android::hardware::radio::V1_6::RadioError::NONE,
                  ::android::hardware::radio::V1_6::RadioError::INVALID_ARGUMENTS}));
     }
+
+    sleep(1);
     serial = GetRandomSerialNumber();
 
     res = radio_v1_6->setDataThrottling(serial, DataThrottlingAction::THROTTLE_ANCHOR_CARRIER,
@@ -453,6 +455,8 @@
                  ::android::hardware::radio::V1_6::RadioError::NONE,
                  ::android::hardware::radio::V1_6::RadioError::INVALID_ARGUMENTS}));
     }
+
+    sleep(1);
     serial = GetRandomSerialNumber();
 
     res = radio_v1_6->setDataThrottling(serial, DataThrottlingAction::HOLD, 60000);
@@ -473,6 +477,8 @@
                  ::android::hardware::radio::V1_6::RadioError::NONE,
                  ::android::hardware::radio::V1_6::RadioError::INVALID_ARGUMENTS}));
     }
+
+    sleep(1);
     serial = GetRandomSerialNumber();
 
     res = radio_v1_6->setDataThrottling(serial, DataThrottlingAction::NO_DATA_THROTTLING, 60000);