Don't crash on SidebarController dispose when app is closing

When app is closing it is possible SfxGetpApp() will return null. So
GetCurrentTheme() cannot return reference to correct theme.
Remember which theme has registered SidebarController to unregister when
disposing.

Change-Id: If223233f621601f445472b0413a56e9c51e59673
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/118970
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>
Reviewed-by: Pranam Lashkari <lpranam@collabora.com>
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/120630
Tested-by: Jenkins
Reviewed-by: Szymon Kłos <szymon.klos@collabora.com>

0 files changed, 0 insertions, 0 deletions