AI: Don't pick most expensive tech as free tech, if it's marked as "0 weight for AI decisions"

core/src/com/unciv/logic/automation/civilization/NextTurnAutomation.kt

@@ -265,8 +265,11 @@ object NextTurnAutomation {
         while(civInfo.tech.freeTechs > 0) {
             val costs = getGroupedResearchableTechs()
             if (costs.isEmpty()) return
-
-            val mostExpensiveTechs = costs[costs.size - 1]
+            
+            val mostExpensiveTechs = costs.lastOrNull{ 
+                // Ignore rows where all techs have 0 weight
+                it.any { it.getWeightForAiDecision(stateForConditionals) > 0 }
+            } ?: costs.last()
             val chosenTech = mostExpensiveTechs.randomWeighted { it.getWeightForAiDecision(stateForConditionals) }
             civInfo.tech.getFreeTechnology(chosenTech.name)
         }