tdf#142817: Correctly replace animation effect that comes with a command

As effect1 with command (e.g. the one from misc/MEDIACALL category)
is created, 'mnCommand' member var is set.

But when it is replaced by command-less effect2 via
CustomAnnimationEffect::replaceNode, this var is never reset (simply
because the relevant if-else branch is never hit) so it looks as if
the command was still there. This causes UI glitch in sidebar:
setting incorrect category of the next selected effect

To fix that, we reset 'mnCommand' in ::setNode function, just as
it is done with resetting audio associated w/ the effect

Change-Id: I86016dd1acadfb31f460bde749bbe15164f1eb81
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/119492
Tested-by: Jenkins
Reviewed-by: Katarina Behrens <bubli@bubli.org>
diff --git a/sd/source/core/CustomAnimationEffect.cxx b/sd/source/core/CustomAnimationEffect.cxx
index b28b9c5..ed61bed 100644
--- a/sd/source/core/CustomAnimationEffect.cxx
+++ b/sd/source/core/CustomAnimationEffect.cxx
@@ -156,6 +156,7 @@ void CustomAnimationEffect::setNode( const css::uno::Reference< css::animations:
{
    mxNode = xNode;
    mxAudio.clear();
    mnCommand = 0;

    const Sequence< NamedValue > aUserData( mxNode->getUserData() );