tdf#164969 tdf#165297 Disable theming by default

commit 924c7de80a
    Date:   Wed Dec 25 23:13:47 2024 +0530

        tdf#164393 [API CHANGE] Make the "Automatic" theme Customizable

had - among others - enabled theming by default, which
results in incorrect colors being used with at least
GTK and Qt based VCL plugins on Linux in the default
configuration, i.e. without any custom color having
been set anywhere.

As discussed in [1], disable theming again by default, by
setting the default for
`officecfg::Office::Common::Appearance::LibreOfficeTheme`
to 0 again.

This implies that custom colors for widgets cannot be
set in "Tools" -> "Options" -> "Appearance" by default
anymore.
In order to set custom colors for those, the above-mentioned
setting can still be set to 1 in the expert settings
(in which case colors can be set for the "Automatic"
theme also, which was implemented in the above-mentioned
commit).

A larger rework of the theming code is in progress,
see Sahil's WIP Gerrit change at [2].

[1] https://gerrit.libreoffice.org/c/core/+/183490/comments/efc32644_52e556d5
[2] https://gerrit.libreoffice.org/c/core/+/183574

Change-Id: I896b7b02a26038f094e044b56f32dbc01cf99ab5
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/183490
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>

officecfg/registry/schema/org/openoffice/Office/Common.xcs

@@ -5209,7 +5209,7 @@
             </info>
           </enumeration>
         </constraints>
-        <value>1</value>
+        <value>0</value>
       </prop>
       <prop oor:name="ApplicationAppearance" oor:type="xs:short" oor:nillable="false">
         <info>