Disable from-text stub generation for art.module.intra.core.api

art.module.intra.core.api depends on art.module.public.api
for from-text stub generation, as the generated stubs contain APIs that
are not included in the api signature file generated from this module.
However, setting art.module.public.api as a dependency of
art.module.intra.core.api leads to circular dependency and
requires further bootstrapping to resolve the issue.

This change does not lead to any user-facing changes, as
art.module.intra.core.api is currently being built from-source by
default.

Test: m --no-skip-soong-tests
Bug: 276958307
Change-Id: I857b6ae865925acb8d51723323636e982e45a768