Check legality of unit actions on adjacent tiles on tile change

[psampathkumar]

Describe the bug There's a long standing issue with typical rulesets where legality of the irrigating activity can depend on the irrigation of the adjacent tile. If that adjacent tile loses the irrigation for some reason, we later get an error about unit doing illegal activity.

To Reproduce

1. Irrigate a tile
2. If neighbouring tile loses irrigation during TC, due to some reason you get an error for illegal behaviour

Expected behavior Check in advance, so there is no illegal behaviour

Screenshots If applicable, add screenshots to help explain your problem.

Platform and version (please complete the following information): master

Additional context Port https://github.com/freeciv/freeciv/commit/15d274689daa21a1361491f5348abf37dd56381f