fix(controls): Make mouse bindings for target selection more intuitive (endless-sky#12519)

* Double-clicking on a non-disabled ship no longer attempts to board the nearest disabled ship if one is present in the system.
* Clicking on a ship you have already targeted no longer makes the targeting sound effect if no change has occurred.
* Right mouse button no longer targets ships when the "Control ship with mouse" preference is on.

Author: Amazinite

source/Engine.cpp

@@ -2357,16 +2357,25 @@ void Engine::HandleMouseClicks()
 	bool clickedAsteroid = false;
 	if(clickTarget)
 	{
-		UI::PlaySound(UI::UISound::TARGET);
 		if(mouseButton == secondaryMouseButton)
+		{
+			UI::PlaySound(UI::UISound::TARGET);
 			ai.IssueShipTarget(clickTarget);
-		else
+		}
+		else if(mouseButton == MouseButton::LEFT)
 		{
 			// Left click: has your flagship select or board the target.
 			if(clickTarget == flagship->GetTargetShip())
-				activeCommands |= Command::BOARD;
+			{
+				if(clickTarget->IsDisabled())
+				{
+					UI::PlaySound(UI::UISound::TARGET);
+					activeCommands |= Command::BOARD;
+				}
+			}
 			else
 			{
+				UI::PlaySound(UI::UISound::TARGET);
 				flagship->SetTargetShip(clickTarget);
 				if(clickTarget->IsYours())
 					player.SelectEscort(clickTarget.get(), hasShift);