Revert gain setting in testADRV9002ManualGainControlError

Author: SrikanthPagadarai

test/ADRV9002Tests.m

@@ -321,7 +321,7 @@ function testADRV9002ManualGainControlError(testCase)
             rx.CustomStreamFileName = which('lte_5_cmos_api_68_0_6.stream');
 
             rx.DigitalGainControlModeChannel0 = 'spi';
-            rx.InterfaceGainChannel0 = '0dB';
+            rx.InterfaceGainChannel0 = '6dB';
             verifyError(testCase, @() rx(), ?MException);
         end