fix: Lowercase address and return completion on creation

[LautaroPetaccio]

This PR does two things:

• Returns the is_mapping_complete status when creating a new collection.
• Lowercases the linked_contract_address and linked_contract_network when upserting a new collection.

[coveralls]

Pull Request Test Coverage Report for Build 10726368266

Details

• 2 of 3 (66.67%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.1%) to 71.416%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/Collection/Collection.model.ts	0	1	0.0%
<!--	Total:	2	3	66.67%	-->

Totals
Change from base Build 10672271516:	0.1%
Covered Lines:	3096
Relevant Lines:	4187

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💛 - Coveralls