Revert "add fab insets avoid overlapping"

This reverts commit 5230d3cb6b.

app/lib/presentation/widgets/floating_action_button_inset.dart

@@ -1,34 +0,0 @@
-/*
- * Copyright (c) 2024-2026 Fabian Freund.
- *
- * This file is part of WebLibre
- * (see https://weblibre.eu).
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as
- * published by the Free Software Foundation, either version 3 of the
- * License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-import 'package:flutter/material.dart';
-
-const standardFloatingActionButtonHeight = kMinInteractiveDimension;
-const smallFloatingActionButtonHeight = 40.0;
-
-double floatingActionButtonBottomInset(
-  BuildContext context, {
-  double fabHeight = standardFloatingActionButtonHeight,
-  double extraPadding = 8.0,
-}) {
-  return fabHeight +
-      kFloatingActionButtonMargin +
-      MediaQuery.paddingOf(context).bottom +
-      extraPadding;
-}