[chassis/arista]: Increase LAG Ids to 1024 (#10519)

Why I did it
Today at most 128 LAGs are supported. This is not sufficient if there are many LAGs with just few ports.

How I did it
Increase LAG Ids to 1024 for DNX device.

Author: ysmanman

device/arista/x86_64-arista_7800_sup/chassisdb.conf

@@ -3,4 +3,4 @@ chassis_db_address=127.100.1.1
 midplane_subnet=127.100.0.0/16
 
 lag_id_start=1
-lag_id_end=128
+lag_id_end=1024