Add Avatar to list of customizable columns in Spend docs

The Avatar column is now toggleable in the column selector for
Reports, so the help site should list it as an available column.

Co-authored-by: Mukhriddin Shakhriyorov <mukhrr@users.noreply.github.com>

Author: MelvinBot

docs/articles/new-expensify/reports-and-expenses/Using-Reports-in-New-Expensify.md

@@ -64,6 +64,7 @@ To customize columns:
 
 You can choose from a wide range of columns, including:
 
+- **Avatar** – The profile image of the report submitter
 - **Date** – When the report or expense was created
 - **Submitted** – The date the report was submitted for approval
 - **Total** – The total amount of the report or expense