Fix alt map key and graphical overmap after #36075

Also add alt map key to mod testing to prevent this.
Graphical overmap needs mod font support to be able to be run with CI.

build-scripts/mod_test_blacklist

@@ -1,5 +1,4 @@
 aftershock
-alt_map_key
 Animatronics
 Battery_Overhaul_Legacy_Mode
 blazemod

data/mods/Graphical_Overmap/overmap_terrain.json

@@ -21460,13 +21460,6 @@
     "sym": "à",
     "color": "light_gray"
   },
-  {
-    "type": "overmap_terrain",
-    "id": "house_base",
-    "copy-from": "house_base",
-    "sym": "à",
-    "color": "light_gray"
-  },
   {
     "type": "overmap_terrain",
     "id": "duplex",

data/mods/alt_map_key/overmap_terrain.json

@@ -182,14 +182,6 @@
     "sym": "^",
     "color": "light_green"
   },
-  {
-    "type": "overmap_terrain",
-    "id": "house_base",
-    "copy-from": "house_base",
-    "name": "house",
-    "sym": "^",
-    "color": "light_green"
-  },
   {
     "type": "overmap_terrain",
     "id": "house_prepper",
@@ -887,8 +879,7 @@
     "id": "megastore_1_2_0",
     "copy-from": "megastore_1_2_0",
     "name": "megastore entrance",
-    "color": "i_magenta",
-    "symbol": "M"
+    "color": "i_magenta"
   },
   {
     "type": "overmap_terrain",