Throw exception when origin and destination positions are the same

[cammace]

Causing a crash on Firebase, temporarily fixed it in the testapp activity, this might need to be fixed in mapbox-java too @zugaldia?

[zugaldia]

@cammace yeah, could you please ticket it?

[cammace]

This is actually not an issue for navigation anymore when the navigation session starts with the same positions, it is treated as though you have instantly arrived (as it should 😄).