Further improvements for provider verification (#33670)

This one completes review and check of provider.yaml verifications.
There was one more check - for duplicates - that did not work
as expected. It was hiding errors detected.

This PR fixes it and also adds a bit more diagnostics messagese
on what is actually being checked to give a bit more clue if some
check is not doing what it is supposed to be doing.

Follow up after #33662 and #33640

airflow/providers/google/provider.yaml

@@ -928,9 +928,6 @@ transfers:
     target-integration-name: Google Cloud Storage (GCS)
     how-to-guide: /docs/apache-airflow-providers-google/operators/transfer/gdrive_to_gcs.rst
     python-module: airflow.providers.google.cloud.transfers.gdrive_to_gcs
-  - source-integration-name: Microsoft SQL Server (MSSQL)
-    target-integration-name: Google Cloud Storage (GCS)
-    python-module: airflow.providers.google.cloud.transfers.mssql_to_gcs
   - source-integration-name: Microsoft Azure FileShare
     target-integration-name: Google Cloud Storage (GCS)
     how-to-guide: /docs/apache-airflow-providers-google/operators/transfer/azure_fileshare_to_gcs.rst

airflow/providers/microsoft/azure/provider.yaml

@@ -245,9 +245,6 @@ transfers:
     target-integration-name: Microsoft Azure Blob Storage
     how-to-guide: /docs/apache-airflow-providers-microsoft-azure/transfer/local_to_wasb.rst
     python-module: airflow.providers.microsoft.azure.transfers.local_to_wasb
-  - source-integration-name: Microsoft Azure Blob Storage
-    target-integration-name: Google Cloud Storage (GCS)
-    python-module: airflow.providers.microsoft.azure.transfers.azure_blob_to_gcs
   - source-integration-name: SSH File Transfer Protocol (SFTP)
     target-integration-name: Microsoft Azure Blob Storage
     how-to-guide: /docs/apache-airflow-providers-microsoft-azure/transfer/sftp_to_wasb.rst