NR S06a: Fix & improve gold carryover

Have objectives match endlevel.
Bump carryover so a more impressive amount is stored next scenario.

On my easy level playthrough I only had 680 carryover. This
change makes it be around 1700 instead.

[ci skip]

data/campaigns/Northern_Rebirth/scenarios/06a_Old_Friend.cfg

@@ -259,7 +259,7 @@
             [/objective]
 
             [gold_carryover]
-                carryover_percentage=0
+                carryover_percentage=100
             [/gold_carryover]
         [/objectives]
     [/event]
@@ -547,7 +547,7 @@
         [endlevel]
             result=victory
             bonus=no
-            {NEW_GOLD_CARRYOVER 40}
+            {NEW_GOLD_CARRYOVER 100}
         [/endlevel]
     [/event]