Fix PanelLayout Task::SetPriority warning

SetStyle will tigger a resize event, which in turn will start the
m_aPanelLayoutIdle, before it's actually prepared, resulting in
the Task::SetPriority SAL_WARN_IF triggering.

Change-Id: Ide48d6004e242cf75bb48dc9f5e8dc3aa5ff809b
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/97664
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>
diff --git a/sfx2/source/sidebar/PanelLayout.cxx b/sfx2/source/sidebar/PanelLayout.cxx
index e4cf889..6a33381 100644
--- a/sfx2/source/sidebar/PanelLayout.cxx
+++ b/sfx2/source/sidebar/PanelLayout.cxx
@@ -21,11 +21,12 @@ PanelLayout::PanelLayout(vcl::Window* pParent, const OString& rID, const OUStrin
    , m_bInClose(false)
    , mxFrame(rFrame)
{
    SetStyle(GetStyle() | WB_DIALOGCONTROL);
    m_aPanelLayoutIdle.SetPriority(TaskPriority::RESIZE);
    m_aPanelLayoutIdle.SetInvokeHandler( LINK( this, PanelLayout, ImplHandlePanelLayoutTimerHdl ) );
    m_aPanelLayoutIdle.SetDebugName("sfx2::PanelLayout m_aPanelLayoutIdle");

    SetStyle(GetStyle() | WB_DIALOGCONTROL);

    // Builder will trigger resize and start Idle
    m_xVclContentArea = VclPtr<VclVBox>::Create(this);
    m_xVclContentArea->Show();