Notify other tasks that OTA is stopped when fail to activate new image.

[ActoryOu]

Notify other tasks that OTA is stopped when fail to activate new image.

Description

As #73 discussed (in additional question), when OTA fail to activate new image, we should notify other tasks to continue.

Test Steps

1. Run OTA test with hacking that OTA pal fail to activate the image like below.

   OtaErr_t OTA_ActivateNewImage( void )
   {
   // skip for simplify
   
   if( ( otaAgent.pOtaInterface != NULL ) && ( otaAgent.pOtaInterface->pal.activate != NULL ) )
   {
       // comment out below line to make activation fail to test this scenario.
       // palStatus = otaAgent.pOtaInterface->pal.activate( &( otaAgent.fileContext ) );
   }
   
   // skip for simplify
   
   return ( ( palStatus >> OTA_PAL_SUB_BITS ) == ( uint32_t ) OtaPalSuccess ) ? OtaErrNone : OtaErrActivateFailed;
   }

2. Check if publish demo is running normally.

Checklist:

• [x] I have tested my changes. No regression in existing tests.
• [ ] I have modified and/or added unit-tests to cover the code changes in this Pull Request.

Related Issue

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