Tree breaks if message definition changes

[Oberacda]

When a tree has an explicit message definition inside of it (constant, etc.), the tree will break if the message is updated to have more fields. The changed message definition is already caught by bt_py, so why not offer some sort of migration?

[Oberacda]

During the discussion, some questions emerged that require additional testing:

• Do existing connections break if new fields are added to a message/service/action, but the connected ones are unchanged?
• Do existing connections break if the field is removed from the message?
• Can we automatically fix/migrate the tree to alleviate these issues?