Guard against UI Info not available causing crash

Always how command description. Better support for VTOL Takeoff. New help text for altitude on Land commands.

Change some descriptions to be more understandable/correct. Change some Heading->Yaw labels. Use new isLandCommand setting.

Fix file extension appending

Fix RadioButton group problems. Rework RTL settings to match correct usage.

Fix RadioButton group problems

Survey And Corridor now share same transect generation code. Better unit tests for both with more coverage.

Force consistent setting for offline vehicle

Use only default values when running unit tests

Visual tweaks for mission items

Cherry pick from master