[Application] Fixed behaviour of launch() function

[Application] Fixed behaviour of launch() function

[Bug] Behaviour of launch() function changed.
For already launched application, now force launch is processed.
Before changing internal implementation, application was resumed
in this case.

With changing app_control_send_launch_request() call to
app_control_send_resume_request() this problem was fixed.

[Verification] binary tizen-5.5-unified_20200219.2 - TW3
PLM P191224-08332 - issue resolved.
Application TCT passrate 100%

Change-Id: I0ab3672e3a64cfbd3bb18d54e71acf562cfa3ff3