admin parametres: hr separator between current/new password, drop new-password top border

app/public/assets/css/admin.css

@@ -1369,6 +1369,13 @@ th.admin-ap-col {
 	border-top: none;
 }
 
+/* Separator between the current and new password inputs */
+.param-form .param-password-separator {
+	border: 0;
+	border-top: 1px solid var(--border-primary);
+	margin: 0;
+}
+
 .param-form fieldset {
   display: flex;
   flex-direction: column;

app/templates/admin/parametres.php

@@ -173,9 +173,10 @@
                     <input type="password" id="current_password"
                            name="current_password" required autocomplete="current-password">
                 </div>
+                <hr class="param-password-separator">
                 <?php endif; ?>
 
-                <div>
+                <div class="param-form-row--flush">
                     <label for="new_password">Nouveau mot de passe</label>
                     <input type="password" id="new_password"
                            name="new_password" required autocomplete="new-password"