fix: ORM-1269 fix found issues (#5564)
The integration with prisma/prisma uncovered two bugs in the current
implementation of the default schema paths.
a) A migrate test was failing due to incorrect schema filter
validations. The logic for this had to be updated to better follow the
updated semantic.
b) Tests related to db push commands and multi schema uncovered that we
were doing e.g. data loss checks on the default schema even if the
default schema is not in the list of explicitly set schemas in the
datasource block.
Integration in prisma/prisma now works. See
https://github.com/prisma/prisma/pull/27742
