related tdf#111733 svx: SfxVoidItem != SvxKerningItem

When selecting text containing several different
kerning values, the pItem returned is a VoidItem.

This was showing up as random numbers in the
TextCharacterSpacingControl spinbutton.

Change-Id: I94cfc566daa42e0d8c3d403eb08af659f01e6d5b
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/129270
Tested-by: Jenkins
Reviewed-by: Justin Luth <jluth@mail.com>
diff --git a/svx/source/sidebar/text/TextCharacterSpacingControl.cxx b/svx/source/sidebar/text/TextCharacterSpacingControl.cxx
index 3da7239..ba528d7 100644
--- a/svx/source/sidebar/text/TextCharacterSpacingControl.cxx
+++ b/svx/source/sidebar/text/TextCharacterSpacingControl.cxx
@@ -109,7 +109,7 @@ void TextCharacterSpacingControl::Initialize()
    const SfxPoolItem* pItem;
    SfxItemState eState = SfxViewFrame::Current()->GetBindings().GetDispatcher()->QueryState(SID_ATTR_CHAR_KERNING, pItem);

    const SvxKerningItem* pKerningItem = static_cast<const SvxKerningItem*>(pItem);
    const SvxKerningItem* pKerningItem = dynamic_cast<const SvxKerningItem*>(pItem);
    tools::Long nKerning = 0;

    if(pKerningItem)