When the Printer stops it needs to clean the last line if it was transient progress

This will show both when stopping everything and when calling pause.

For example, check the two following codes:
```
emit.progress("Long text")
time.sleep(5)
with emit.pause():
print("inside")
emit.message("Done")
```

and

```
emit.progress("Long text")
time.sleep(5)
```

In the first case the text `inside` should overwrite "Long text", and in the second case whatever comes next because the process ends (e.g. the shell prompt) it should overwrite "Long text".

IOW, "Long text" should not remain in the screen after "the next thing comes" (because it's transient progress).