electron-source.electron_39: remove, electron_39-bin: mark as insecure (#521310)

pkgs/development/tools/electron/binary/generic.nix

@@ -61,7 +61,7 @@ let
     ];
     sourceProvenance = with lib.sourceTypes; [ binaryNativeCode ];
     # https://www.electronjs.org/docs/latest/tutorial/electron-timelines
-    knownVulnerabilities = lib.optional (lib.versionOlder version "39.0.0") "Electron version ${version} is EOL";
+    knownVulnerabilities = lib.optional (lib.versionOlder version "40.0.0") "Electron version ${version} is EOL";
   };
 
   fetcher =

pkgs/top-level/all-packages.nix

@@ -5276,10 +5276,7 @@ with pkgs;
       in
       {
         electron_38 = electron_38-bin;
-        electron_39 = getElectronPkg {
-          src = electron-source.electron_39;
-          bin = electron_39-bin;
-        };
+        electron_39 = electron_39-bin;
         electron_40 = getElectronPkg {
           src = electron-source.electron_40;
           bin = electron_40-bin;