stellarium: make qtwebengine an optional dependency (#349497)

pkgs/by-name/st/stellarium/package.nix

@@ -17,6 +17,7 @@
   xvfb-run,
   gitUpdater,
   md4c,
+  withQtWebEngine ? lib.meta.availableOn stdenv.hostPlatform qt6.qtwebengine,
 }:
 
 stdenv.mkDerivation (finalAttrs: {
@@ -59,7 +60,6 @@ stdenv.mkDerivation (finalAttrs: {
     qt6.qtpositioning
     qt6.qtmultimedia
     qt6.qtserialport
-    qt6.qtwebengine
     calcmysky
     qt6Packages.qxlsx
     indilib
@@ -70,6 +70,9 @@ stdenv.mkDerivation (finalAttrs: {
   ]
   ++ lib.optionals stdenv.hostPlatform.isLinux [
     qt6.qtwayland
+  ]
+  ++ lib.optionals withQtWebEngine [
+    qt6.qtwebengine
   ];
 
   preConfigure = ''