miral-app -launcher <app> sometimes causes egl image bad alloc

This comes from a failed attempt to "bypass" a fullscreen surface from a Wayland client. Simply not bypassing for this case works around the issue:

- if (!native)
- BOOST_THROW_EXCEPTION(std::invalid_argument("could not convert NativeBuffer"));
- if (native->flags & mir_buffer_flag_can_scanout &&
+ if (native && native->flags & mir_buffer_flag_can_scanout &&

But this loses efficiency.

Root cause:

class WaylandBuffer :
...
    std::shared_ptr<mir::graphics::NativeBuffer> native_buffer_handle() const override
    {
        return nullptr;
    }

Root cause:

class WaylandBuffer :
...
    std::shared_ptr<mir::graphics::NativeBuffer> native_buffer_handle() const override
    {
        return nullptr;
    }

But this isn't quick to fix.

So I'll offer up the above fix and log the lack of bypass as a performance issue.

Fix committed into lp:mir at revision None, scheduled for release in mir, milestone Unknown