In behavior annex plugin: unit is not set for timed actions

## Summary

When we have TimedAction statement in the BA, the time unit is not set in the model after name resolution.

## Expected and Current Behavior
When writing 

``àadl
computation(4 us..5us)
```
in a BA subclause, the corresponding model after parsing and name resolution does not contain the unit.

## Environment

* **OSATE Version**: 2.3.5
* **Operating System**: Linux
