Add building of TV example to gn_build.sh (#6903)
Add building of TV example to gn_build.sh (#6903)

Problem
TV example app is not built using gn_build.sh script

Summary of Changes
- Updated the ./BUILD.gn to support building of tv-example-app

Test
Used the ./gn_build.sh to verify the building is successful
nestlabs/connectedhomeip,nestlabs/connectedhomeip,project-chip/connectedhomeip,project-chip/connectedhomeip,nestlabs/connectedhomeip,nestlabs/connectedhomeip,project-chip/connectedhomeip,project-chip/connectedhomeip,nestlabs/connectedhomeip,nestlabs/connectedhomeip,project-chip/connectedhomeip,nestlabs/connectedhomeip,project-chip/connectedhomeip