refactor(schematics): make project option visible

[emilio-martinez]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/ngrx/platform/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Documentation has been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[X] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Other... Please describe:

What is the current behavior?

Schematics project flag not visible.

Closes #1512

What is the new behavior?

Schematics project flag is now visible.

Does this PR introduce a breaking change?

[ ] Yes
[X] No

Other information

[ngrxbot]

Preview docs changes for e1f5267 at https://previews.ngrx.io/pr1518-e1f5267/

[brandonroberts]

Thanks @emilio-martinez!