Fix: Extended spawn immunity in 1v1s (#3010) (#3028)

If this PR fixes an issue, link it below. If not, delete these two
lines.
Resolves #3010 

## Description:

Extended the spawn immunity in 1v1s from 5 to 30 seconds, to prevent
spawn killing.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

@xtonai

Co-authored-by: Ryan <7389646+ryanbarlow97@users.noreply.github.com>

src/server/MapPlaylist.ts

@@ -171,7 +171,7 @@ export class MapPlaylist {
       disableNations: true,
       gameMode: GameMode.FFA,
       bots: 100,
-      spawnImmunityDuration: 5 * 10,
+      spawnImmunityDuration: 30 * 10,
       disabledUnits: [],
     } satisfies GameConfig;
   }