Please find updated patch. Now placeholder string for bytea and bytea[] data will only appear in datagrid (view all/1000/500 rows). If user executes query using Query tool then placeholder won't appear (similar to pgAdminIII behaviour)
This broke the fetching trigger function parameters logic, take a look at raise_a_notice() function parameter in screenshot.
In my opinion we just can't just blindly convert everything to place holder, what if user wants to perform some operation on bytea column like we are doing in web/pgadmin/browser/server_groups/servers/databases/schemas/tables/templates/trigger/sql/default/properties.sql to fetch these arguments?
Please find attached patch to handle bytea and bytea[] data in datagrid.
Now instead of showing actual data we can show placeholders like <binary data> and <binary data[]>. Also placeholders will only appear if data actually exists otherwise null will be shown.