Avoid building extra-deps when passing --force-dirty

### General Comments

It is not obvious to me whether this in the intended behaviour or not. If this *is* the intended behaviour, then this is a feature request to make it so that we can force either the local packages or the local packages and all extra-deps as dirty.

If this is a bug, then it's very possibly a dupe of #1940

### Steps to reproduce

```
packages:
- '.'
- location: /home/rlpowell/src/pandoc
extra-dep: true
````

Run ```stack build --force-dirty```

### Expected

My project rebuilds, but pandoc does not.

### Actual

Both my local pandoc and my project rebuild.