Revise inter-boundary-component-has-direction constraint (#930)

[DimitriZhurkin]

Committer Notes

1. In fedramp-external-constraints.xml, modify the target Metapath expression (the inter-boundary-component variable).
2. Update ssp-inter-boundary-component-has-direction-INVALID.xml to reflect Metapath changes.

Related issue: #930

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[aj-stein-gsa]

I would like this PR not get merged until we confirm this implements the updated in a comment but not modified in the issue criteria per #930 (comment). I just want confirmation that this is "the place" where that goes because thus far the new requirements were discussed separate of which issue, this seems like one possible place. If I get corrected by someone on the team, I will dismiss and approve.

[aj-stein-gsa]

I only delinked #930 so it does not automatically close the issue because there are potentially multiple requirements for that set of constraints, I do not want to automatically close. I am about to re-review.