Use slightly less informal wording for applet error

Some folks complained about this, and the original change was not fully
approved of by everyone. Hopefully this compromise generates less
friction.

desktoppackage/contents/applet/AppletError.qml

@@ -49,7 +49,7 @@ Item {
         }
 
         PlasmaExtras.Heading {
-            text: i18nd("plasma_shell_org.kde.plasma.desktop", "Oops! There was an error loading %1.", root.errorInformation.appletName)
+            text: i18nd("plasma_shell_org.kde.plasma.desktop", "Sorry! There was an error loading %1.", root.errorInformation.appletName)
             level: 2
             wrapMode: Text.Wrap
             horizontalAlignment: Text.AlignHCenter