Remove pointless assertion

After cc93fa1d10 the function handles
viewShell being null so no need to fail an assert if it is null.

Change-Id: Ie7d398f300e5eb695ae249291b9b8611dddc6423
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/189865
Reviewed-by: Caolán McNamara <caolan.mcnamara@collabora.com>
Tested-by: Jenkins

desktop/source/lib/init.cxx

@@ -2406,7 +2406,6 @@ void CallbackFlushHandler::enqueueUpdatedTypes()
     assert(m_viewId >= 0);
     SfxViewShell* viewShell = SfxViewShell::GetFirst( false,
         [this](const SfxViewShell& shell) { return shell.GetViewShellId().get() == m_viewId; } );
-    assert(viewShell != nullptr);
 
     // First move data to local structures, so that callbacks don't possibly modify it.
     std::vector<bool> updatedTypes;