Change defaultButton type to "button"

(cherry picked from commit 7ddb52a)

Author: matthew-darby

src/Umbraco.Web.UI.Client/src/views/documenttypes/edit.controller.js

@@ -176,7 +176,7 @@
                     hotKeyWhenHidden: true,
                     labelKey: vm.submitButtonKey,
                     letter: "S",
-                    type: "submit",
+                    type: "button",
                     handler: function () { vm.save(); }
                 };
                 vm.page.subButtons = [{

src/Umbraco.Web.UI.Client/src/views/mediatypes/edit.controller.js

@@ -190,7 +190,7 @@
                     hotKeyWhenHidden: true,
                     labelKey: vm.saveButtonKey,
                     letter: "S",
-                    type: "submit",
+                    type: "button",
                     handler: function () { vm.save(); }
                 };
                 vm.page.subButtons = [{

src/Umbraco.Web.UI.Client/src/views/membertypes/edit.controller.js

@@ -111,7 +111,7 @@
                     hotKeyWhenHidden: true,
                     labelKey: vm.saveButtonKey,
                     letter: "S",
-                    type: "submit",
+                    type: "button",
                     handler: function () { vm.save(); }
                 };
                 vm.page.subButtons = [{