backstage/.changeset/dirty-bugs-care.md

@backstage/test-utils, @backstage/test-utils-core

@backstage/test-utils	@backstage/test-utils-core
patch	patch

Migrates all utility methods from test-utils-core into test-utils and delete exports from the old package. This should have no impact since this package is considered internal and have no usages outside core packages.

Notable changes are that the testing tool msw.setupDefaultHandlers() have been deprecated in favour of setupRequestMockHandlers().