Fix: AI window did not update button disabled state when changing values. (#11527)

(cherry picked from commit 0b1429ce14)

src/ai/ai_gui.cpp

@@ -199,6 +199,7 @@ struct AIConfigWindow : public Window {
 					new_value = std::min(MAX_COMPANIES - 1, GetGameSettings().difficulty.max_no_competitors + 1);
 				}
 				IConsoleSetSetting("difficulty.max_no_competitors", new_value);
+				this->InvalidateData();
 				break;
 			}
 
@@ -211,6 +212,7 @@ struct AIConfigWindow : public Window {
 					new_value = std::min(static_cast<int>(MAX_COMPETITORS_INTERVAL), GetGameSettings().difficulty.competitors_interval + 1);
 				}
 				IConsoleSetSetting("difficulty.competitors_interval", new_value);
+				this->InvalidateData();
 				break;
 			}