Fix mirvhead spamming same location (#801)

## Description:
There is a bug in the proximity check in the mirvhead destination 

This fixes it.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

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

Vivacious Box

src/core/execution/MIRVExecution.ts

@@ -169,10 +169,8 @@ export class MirvExecution implements Execution {
       if (this.mg.owner(tile) !== this.targetPlayer) {
         continue;
       }
-      for (const t of taken) {
-        if (this.mg.manhattanDist(tile, t) < 25) {
-          continue;
-        }
+      if (this.proximityCheck(tile, taken)) {
+        continue;
       }
       return tile;
     }
@@ -180,6 +178,15 @@ export class MirvExecution implements Execution {
     return null;
   }
 
+  private proximityCheck(tile: TileRef, taken: TileRef[]): boolean {
+    for (const t of taken) {
+      if (this.mg.manhattanDist(tile, t) < 25) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   owner(): Player {
     return this.player;
   }