[Tizen] hardcode OZONE_WAYLAND_USE_XDG_SHELL enviroment in service file

This commit force the use of this feature on wayland
(used by tizen's Application.hide() )
in case it's not started from a login shell.

Alternative would be to force a login shell (sh -l -c "...")
and rely on system wide env as introduced
by my other commit about this variable.

But for performance concern it's hardcoded there,
this change may be reverted
if Tizen sessions decide to use login shells then it will work same.

Refer to this page for xdg-shell integration in Tizen :

https://wiki.tizen.org/wiki/Wayland_xdg-shell_protocol
[Tizen] packaging: enable xdg-shell with OZONE_WAYLAND_USE_XDG_SHELL

Since this wayland extension is still unstable,
ozone-wayland does now build it but in disabled state by default
so it needs to be enabled on purpose in Tizen's at run time.

To toggle it on, a simple env variable OZONE_WAYLAND_USE_XDG_SHELL
must be defined in user env.
System wide '/etc/profile' mechanism is used
to ensure consistant environment in every login shells.

Note this change relies on
updated version of ozone-wayland to be effective
without it will not cause any arm.

Refer to this page for xdg-shell integration in Tizen :

https://wiki.tizen.org/wiki/Wayland_xdg-shell_protocol