[fix][#33328] @media css for modal windows on iPhone. Fixes #3169

Today, not really possible to use responsive admin on an iPhone device (not possible to navigate in modal windows)
This PR is forcing css for small device, and give user scrollability on iOS devices.

modal windows on Mobile Devices

Adapts size and position for Modal windows (iframe), if device width is under 979 (small and x-small devices).

modal windows on Mobile Devices (touch for iOS)

Adds media css for device with a width lower 979.
Adds touching scroll if screen size lower 979 (overflow: scroll needed for iOS devices)

modal windows on Mobile Devices

Adapts size and position for Modal windows (iframe), if device width is under 979 (small and x-small devices).

Removes " hidden-phone" class for Submit toolbar

To enhance usage of modal windows on mobile device, removal of "hidden-phone" class for the submit toolbar.
Needed, for example on iPhone, to be able to use Users modal box search function.