Metrics on pings with include_client_identifier: false should not generate SQL expecting a client_id or a sample_id

[chutten]

e.g. https://dictionary.telemetry.mozilla.org/apps/firefox_desktop/metrics/network_content_decoding_error_report

When you generate the SQL for it, it's almost correct. However, there is no client_info column group at all (the ping has no info sections (it's glean.min.1) and, absent of a client_id, the sample_id filter filters out all rows.