Do not run "Send to dock" mission if the robot is docked

[andchiind]

Describe the improvement you would like to see
If ISAR reports that the robot is already docked, we don't need to schedule a "send to dock" or "return home" mission. See equinor/isar#680

How will this change existing functionality?
It is a minor change, but it will prevent us from needing to ignore illogical missions from Flotilla in ISAR.

How will this improvement affect the current Threat Model?
N/A