Bump minimum google-api-core to 2.30.3 to fix Dag import timeout (#67774)

google-api-core 2.28.1 introduced an import-time performance regression:
a Python-version check added to google/api_core/__init__.py calls
importlib.metadata.packages_distributions(), which scans every installed
package on each import. In a large Airflow venv this adds several seconds
to importing google.api_core and anything built on it, pushing the import
of operators like DataprocCreateBatchOperator and BigQueryInsertJobOperator
past the Dag file import timeout.

Fixed upstream in google-api-core 2.30.3
(googleapis/google-cloud-python#16579); a maintainer confirmed on the issue
that upgrading to 2.30.3 cuts import time from 30-50s to 2-5s.

This raises the google provider floor to google-api-core>=2.30.3, excluding
the regressed 2.28.1-2.30.2 range. The previous !=2.16.0,!=2.18.0 exclusions
are subsumed by the higher floor and dropped. uv.lock already resolves to
2.30.3, so only the recorded specifier changes.

closes: #62373