How to remove white color circular border in google devices like pixel

Here is step :

Go to tiapp.xml
Edit android->mainfest->application touple
Previously it was :

<application android:theme="@style/Theme.connectMobileTheme" >
After changed :

<application android:theme="@style/Theme.connectMobileTheme" android:roundIcon="@mipmap/ic_launcher_round" android:icon="@drawable/appicon" >

This will manipulate below file :
/Projects/titanium/build/android/AndroidManifest.xml file to apply.

For this you required to maintain icon inside /Projects/titanium/platform/android/res/

https://i.stack.imgur.com/34c0N.png