fix: close button unresponsive on Android tablets in file picker modal

The modal-container__content element was receiving overflow-y: auto via the
NMC theme override, turning it into a scroll container. On Android Chrome,
this scroll container intercepts touch events in its rendered bounds — which
overlaps with the absolutely-positioned close button (top: 0.5rem, right: 0.5rem).
As a result, tapping the X button had no effect on Android tablets (tested on
Samsung Galaxy Tab A8 / Android 14 and Lenovo Tab M10 / Android 12).

NcDialog intentionally sets modal-container__content to overflow: hidden and
handles scrolling one level deeper at dialog__content. The NMC override was
defeating this by making the outer container a touch scroll target.

Fix: separate the combined &__content, .dialog__content selector so that
overflow-y: auto only applies to .dialog__content (where scrolling belongs),
leaving modal-container__content without an overflow override. NcDialog's
own scoped CSS (overflow: hidden) now applies correctly, eliminating the
touch event interception on Android.

Author: suet-kei-chan

css/layouts/modal.scss

@@ -59,8 +59,7 @@
                     touch-action: manipulation;
                 }
 
-                &__content, .dialog__content {
-                    overflow-y: auto;
+                &__content {
                     padding-inline: 0;
 
                     .button-vue--vue-secondary {
@@ -126,6 +125,11 @@
                     }
                 }
 
+                .dialog__content {
+                    overflow-y: auto;
+                    padding-inline: 0;
+                }
+
                 &:has(.modal__content--exif) {
                     padding: 0;