sw: drop obsolete check. Minimum GCC version is 13

Since
commit 16dd61ab4d
Author: Ilmari Lauhakangas <ilmari.lauhakangas@libreoffice.org>
Date:   Sat Mar 21 08:40:09 2026 +0200

    Bump minimum GCC version to 13

Change-Id: I36ffe36a98957f8917777d2b998dbabc57e39a22
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/208846
Reviewed-by: Xisco Fauli <xiscofauli@libreoffice.org>
Tested-by: Jenkins

sw/source/core/txtnode/modeltoviewhelper.cxx

@@ -187,17 +187,9 @@ ModelToViewHelper::ModelToViewHelper(const SwTextNode &rNode,
                     if (::std::all_of(startedFields.begin(), startedFields.end(),
                             [](auto const& it) { return it.second; }))
                     {
-// prevent -Werror=maybe-uninitialized under gcc 11.2.0
-#if defined __GNUC__ && !defined __clang__ && __GNUC__ == 12
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
-#endif
                         // i is still hidden but the Range end is oddly "-1"
                         aHiddenMulti.Select({*oStartHidden, i}, true);
                         oStartHidden.reset();
-#if defined __GNUC__ && !defined __clang__ && __GNUC__ == 12
-#pragma GCC diagnostic pop
-#endif
                     }
                     break;
                 }