Initialize new Frontend params as nullptr

Bug: 288170590
Test: m
Change-Id: Ic5fdf73d5221f2a04232f3820cbf84fb31c135e4

tv/tuner/aidl/default/Frontend.cpp

@@ -34,6 +34,8 @@ Frontend::Frontend(FrontendType type, int32_t id) {
     mTuner = nullptr;
     // Init callback to nullptr
     mCallback = nullptr;
+    mIptvPluginInterface = nullptr;
+    mIptvPluginStreamer = nullptr;
 
     switch (mType) {
         case FrontendType::ISDBS: {