Remove database constraint check_508774aac0

What does this MR do and why?

Remove contraint check_508774aac0

Related to #377433 (closed)

Migration outpout

$ bin/rails db:migrate:up:main VERSION=20221018081416
main: == 20221018081416 MembersRemoveMemberNamespaceIdNotNullConstraint: migrating ==
main: -- transaction_open?()
main:    -> 0.0000s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- execute("ALTER TABLE members\nDROP CONSTRAINT IF EXISTS check_508774aac0\n")
main:    -> 0.0128s
main: == 20221018081416 MembersRemoveMemberNamespaceIdNotNullConstraint: migrated (0.0173s) 

$ bin/rails db:migrate:down:main VERSION=20221018081416
main: == 20221018081416 MembersRemoveMemberNamespaceIdNotNullConstraint: reverting ==
main: -- current_schema()
main:    -> 0.0006s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- current_schema()
main:    -> 0.0003s
main: -- transaction_open?()
main:    -> 0.0000s
main: -- execute("ALTER TABLE members\nADD CONSTRAINT check_508774aac0\nCHECK ( member_namespace_id IS NOT NULL )\nNOT VALID;\n")
main:    -> 0.0013s
main: == 20221018081416 MembersRemoveMemberNamespaceIdNotNullConstraint: reverted (0.0232s) 

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.