Fix issue a cause of "Could not find step name".

This was happening because the code to generate step names was not excluding units that would not participate in combat, resulting in infrastructure units getting their own steps (which later did not match what the engine generated once the filtering took place).

Uses the same logic as what's done for the battle to exclude units.

Fixes: #10647

game-app/game-core/src/main/java/games/strategy/triplea/delegate/battle/steps/fire/general/FiringGroupSplitterGeneral.java

@@ -56,10 +56,28 @@ public enum Type {
 
   @Override
   public List<FiringGroup> apply(final BattleState battleState) {
+    final Collection<Unit> enemyUnits =
+        CollectionUtils.getMatches(
+            battleState.filterUnits(ALIVE, side.getOpposite()),
+            PredicateBuilder.of(Matches.unitIsNotInfrastructure())
+                .andIf(side == DEFENSE, Matches.unitIsSuicideOnAttack().negate())
+                .andIf(side == OFFENSE, Matches.unitIsSuicideOnDefense().negate())
+                .build());
+
+    // Filter participants (same as is done in MustFightBattle.removeNonCombatants()), so that we
+    // don't end up generating combat step names for units that will be excluded.
+    final Predicate<Unit> canParticipateInCombat =
+        Matches.unitCanParticipateInCombat(
+            side == OFFENSE,
+            battleState.getPlayer(OFFENSE),
+            battleState.getBattleSite(),
+            1,
+            enemyUnits);
     final Collection<Unit> canFire =
         CollectionUtils.getMatches(
             battleState.filterUnits(ACTIVE, side),
             PredicateBuilder.of(getFiringUnitPredicate(battleState))
+                .and(canParticipateInCombat)
                 // Remove offense allied units if allied air can not participate
                 .andIf(
                     side == OFFENSE
@@ -68,14 +86,6 @@ public List<FiringGroup> apply(final BattleState battleState) {
                     Matches.unitIsOwnedBy(battleState.getPlayer(side)))
                 .build());
 
-    final Collection<Unit> enemyUnits =
-        CollectionUtils.getMatches(
-            battleState.filterUnits(ALIVE, side.getOpposite()),
-            PredicateBuilder.of(Matches.unitIsNotInfrastructure())
-                .andIf(side == DEFENSE, Matches.unitIsSuicideOnAttack().negate())
-                .andIf(side == OFFENSE, Matches.unitIsSuicideOnDefense().negate())
-                .build());
-
     final List<FiringGroup> firingGroups = new ArrayList<>();
 
     final List<TargetGroup> targetGroups = TargetGroup.newTargetGroups(canFire, enemyUnits);