Fix deadlocks of `make screenshot` tests

...like CppunitTest_sw_dialogs_test after
a1700d52 "tdf#124238 - Show a Tip-Of-The-Day
dialog on startup" (see my comment from today at
<https://gerrit.libreoffice.org/#/c/69498/> "tdf#124238 - Show a Tip-Of-The-Day
dialog on startup").

As it is unlikely that any test would actually want the Tip-Of-The-Day dialog to
appear, just set the corresponding configuration property to false so that all
tests using gb_CppunitTest_use_unittest_configuration no longer show it.

(<https://gerrit.libreoffice.org/#/c/69498/21..22/sfx2/source/view/viewfrm.cxx>
had added the --nofirststartwizard resp. later --nologo hack to
SfxViewFrame::Notify in sfx2/source/view/viewfrm.cxx, in response to
<https://gerrit.libreoffice.org/#/c/69498/21> failing in UITest_hide_cols.
However, that hack is not obsoleted by this change, as those UITest apparently
don't use gb_CppunitTest_use_unittest_configuration.)

Change-Id: I365e04eb1a3ec0b50f64d5846fc985f601a2750e
Reviewed-on: https://gerrit.libreoffice.org/70595
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

test/user-template/registry/modifications.xcd

@@ -19,6 +19,9 @@
     <prop oor:name="UseLocking">
       <value>false</value>
     </prop>
+    <prop oor:name="ShowTipOfTheDay">
+      <value>false</value>
+    </prop>
   </node>
   <node oor:name="Filter">
     <node oor:name="Graphic">