Remove leftover AssetManager import (#606)

Author: tomekzaw

android/src/main/java/com/expensify/livemarkdown/MarkdownTextInputDecoratorView.java

@@ -3,7 +3,6 @@
 import androidx.annotation.Nullable;
 
 import android.content.Context;
-import android.content.res.AssetManager;
 import android.text.TextWatcher;
 import android.util.AttributeSet;