Data source `alicloud_cdn_service`: The CDN internet_charge_type shouldn't be modified silently

[WeiZhixiong]

The dataSourceAliCloudCdnServiceRead function in alicloud/data_source_alicloud_cdn_service.go may silently modify the internet_charge_type under specific conditions, potentially causing major issues.

Shouldn't modify the internet_charge_type be an explicit modification?

Why is ModifyCdnService being called in dataSourceAliCloudCdnServiceRead? This is a read method, not a modify method

[xuzhang3]

@WeiZhixiong Sorry we lost the info why add the update to the data source. This is a code compliance violation, it should be a resource instead of a data source. We will fix this in the future.