fix: version 2.8.6 -- flecha roja mas visible para ocultar logos de marca

El boton "-" para colapsar el catalogo de marcas casi no se distinguia; se reemplaza por una
flecha hacia arriba en rojo (ChevronUp), mucho mas clara.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

frontend/src/pages/Contrasenas/ContrasenasPage.jsx

@@ -1,7 +1,7 @@
 import { useEffect, useState } from 'react';
 import { useNavigate } from 'react-router-dom';
 import {
-  Plus, Minus, Trash2, Eye, EyeOff, Copy, Pencil, Save, X, RefreshCw, ShieldAlert, MoreVertical,
+  Plus, ChevronUp, Trash2, Eye, EyeOff, Copy, Pencil, Save, X, RefreshCw, ShieldAlert, MoreVertical,
   Mail, Globe, Server, Database, Cloud, Shield, Lock, Wifi, CreditCard, Building2, Printer,
   Smartphone, KeyRound, HardDrive, Router, UserCog,
 } from 'lucide-react';
@@ -366,11 +366,11 @@ export default function ContrasenasPage() {
                   <span className="text-muted" style={{ fontSize: '.72rem' }}>{t('vault_icon_more')}</span>
                   <button
                     type="button"
-                    className="icon-btn"
+                    className="icon-btn vault-icon-collapse-btn"
                     title={t('vault_icon_less')}
                     onClick={() => setShowBrandIcons(false)}
                   >
-                    <Minus size={14} />
+                    <ChevronUp size={18} />
                   </button>
                 </div>
                 <div className="vault-icon-picker vault-icon-picker-brands">