Advanced Mapping Fields Should Not Reference "Post" Analytics Fields

Issue in ./help/sources/connectors/adobe-applications/mapping/analytics.md

The entirety of the [Advanced Mapping Fields](https://experienceleague.adobe.com/docs/experience-platform/sources/connectors/adobe-applications/mapping/analytics.html?lang=en#advanced-mapping-fields) section of this page makes repeated references to "post" columns from Analytics. The Analytics Data Connector source does not pull in post_ data from Analytics. It pulls in "mid" columns. The mid columns are not accessible to any reporting or ETL tool. As such, the Advanced Mapping Fields would be better off using the "pre" fields from the Analytics data feed, which are the fields that do not contain "post_" in their name.

Open help/sources/connectors/adobe-applications/mapping/analytics.md and review the Advanced Mapping Fields section alongside the linked Analytics mapping documentation. Update the repeated references so the section describes the available pre fields rather than post fields, then verify that no inaccurate post_ references remain.

Written by the indexing model from the issue text.