Remove non-nullable force assert for Long Click Listener in CCB (#360)

FluentUI.Demo/src/main/java/com/microsoft/fluentuidemo/demos/ContextualCommandBarActivity.kt

@@ -150,7 +150,7 @@ class ContextualCommandBarActivity : DemoActivity() {
             })
 
             setItemLongClickListener(object : CommandItem.OnItemLongClickListener {
-                override fun onItemLongClick(item: CommandItem, view: View): Boolean {
+                override fun onItemLongClick(item: CommandItem, view: View) {
                     Toast.makeText(
                         this@ContextualCommandBarActivity,
                         getString(
@@ -159,7 +159,6 @@ class ContextualCommandBarActivity : DemoActivity() {
                         ),
                         Toast.LENGTH_SHORT
                     ).show()
-                    return true
                 }
             })
 

fluentui_ccb/src/main/java/com/microsoft/fluentui/contextualcommandbar/CommandItem.kt

@@ -16,7 +16,7 @@ interface CommandItem {
     }
 
     interface OnItemLongClickListener {
-        fun onItemLongClick(item: CommandItem, view: View): Boolean
+        fun onItemLongClick(item: CommandItem, view: View)
     }
 
     /**

fluentui_ccb/src/main/java/com/microsoft/fluentui/contextualcommandbar/CommandItemAdapter.kt

@@ -159,9 +159,12 @@ internal class CommandItemAdapter(
                     )
                 }
             }
+
             setOnLongClickListener {
-                itemLongClickListener?.onItemLongClick(commandItem, viewHolder.itemView)!!
+                itemLongClickListener?.onItemLongClick(commandItem, viewHolder.itemView)
+                true
             }
+
             setOnClickListener {
                 itemClickListener?.onItemClick(commandItem, viewHolder.itemView)
             }