Fix unit being constructed too early 1

This caused multiple bugs:
1) custom effects were not working on recall list units because units
   were created before lua initialisation (see issue #7234). This can
   cause OOS when the MP "Back to turn" feature is used.
2) (rare) Possible OOS causes by unsynced traits, see the comment
   in game_state.cpp before tb.build_team_stage_two()

src/game_state.cpp

@@ -232,6 +232,9 @@ void game_state::init(const config& level, play_controller & pc)
 		for(team_builder& tb : team_builders) {
 			tb.build_team_stage_two();
 		}
+		for(team_builder& tb : team_builders) {
+			tb.build_team_stage_three();
+		}
 
 		for(std::size_t i = 0; i < board_.teams().size(); i++) {
 			// Labels from players in your ignore list default to hidden

src/teambuilder.cpp

@@ -66,6 +66,10 @@ void team_builder::build_team_stage_one()
 	// If the game state specifies additional units that can be recruited by the player, add them.
 	previous_recruits();
 
+}
+
+void team_builder::build_team_stage_two()
+{
 	// place leader
 	leader();
 
@@ -73,7 +77,7 @@ void team_builder::build_team_stage_one()
 	prepare_units();
 }
 
-void team_builder::build_team_stage_two()
+void team_builder::build_team_stage_three()
 {
 	// place units
 	// this is separate stage because we need to place units only after every other team is constructed

src/teambuilder.hpp

@@ -41,11 +41,13 @@ public:
 	team_builder(const team_builder&) = delete;
 	team_builder(team_builder&&) = default;
 
-	/** Handles the first stage of team initialization (everything except unit placement). */
+	/** Handles the first stage of team initialization (everything except unit construction). */
 	void build_team_stage_one();
 
-	/** Handles the second stage of team initialization (unit placement). */
+	/** Handles the second stage of team initialization ((some) unit construction). */
 	void build_team_stage_two();
+	/** Handles the third stage of team initialization (unit placement). */
+	void build_team_stage_three();
 
 private:
 	int gold_info_ngold_;