chore: Add checks to upserts of TPW collections

[LautaroPetaccio]

This PR does the following:

• Adds a missing check for upserting a collection into a third party (that is, a collection that didn't have urn_suffix or third_party_id now has one).
• Updates the tpwCollectionURNRegex to capture the urn_suffix that was not being captured before.
• Removes duplicated validation schema that was being already checked using the middleware.
• Adds a check to prevent third party collections with published items from changing the collection's URN.

The PR depends on #327, once it gets merged, the branch will be re-pointed to master.
Closes #317

[coveralls]

Pull Request Test Coverage Report for Build 1409400932

• 10 of 10 (100.0%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.3%) to 62.638%

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Totals
Change from base Build 1409388749:	0.3%
Covered Lines:	1622
Relevant Lines:	2438

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💛 - Coveralls

[nicosantangelo]

LGTM