Fix improved hostages AI freezing after map change when bots are disabled

When hostage_ai_enable is set in CS 1.6 but bots are not allowed
(dedicated server without bot_enable), CCSBotManager::LoadNavigationMap
returns early and never frees the navigation mesh of the previous map.
LoadNavigationMap() then sees a non-empty TheNavAreaList and keeps the
stale nav data, so on the next hostage map CHostageImprov is created
against the wrong navigation mesh: hostages freeze and stop responding
to +use.

Destroy the stale navigation data in CHostageManager::ServerActivate
before loading, but only when bots are not allowed - otherwise
CCSBotManager has already reloaded the nav mesh earlier in the same
ServerActivate and holds pointers into it.

Fixes #1161

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: belomaxorka

regamedll/dlls/hostage/hostage.cpp

@@ -1450,6 +1450,11 @@ void CHostageManager::ServerActivate()
 
 #ifdef REGAMEDLL_ADD
 		if (!AreRunningCZero()) {
+			// Free stale navigation data of the previous map,
+			// CCSBotManager::LoadNavigationMap does this only when bots are allowed
+			if (!AreBotsAllowed())
+				DestroyNavigationMap();
+
 			LoadNavigationMap();
 		}
 #endif