LocatorFilterEntry: Get rid of filter field

Remove also c'tor taking a pointer to filter.

Change-Id: Ic0fe62daeb6e79a729bee24d07d7eb77559e19c4
Reviewed-by: Eike Ziller <eike.ziller@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

src/plugins/clangcodemodel/clangdlocatorfilters.cpp

@@ -221,7 +221,6 @@ private:
         const auto docSymbolGenerator = [&](const DocumentSymbol &info,
                                             const LocatorFilterEntry &parent) {
             LocatorFilterEntry entry;
-            entry.filter = this;
             entry.displayName = ClangdClient::displayNameFromDocumentSymbol(
                 static_cast<SymbolKind>(info.kind()), info.name(),
                 info.detail().value_or(QString()));