It is possible to launch Power BI as an embedded application from within Microsoft Teams. Refer to Microsoft: Add the Power BI app to Microsoft Teams.
However, ArcGIS for Power BI is not supported in this environment. This functionality is a limitation imposed by Microsoft, as they do not allow secondary authentication to occur within the Teams application. Therefore, signing in to either an ArcGIS Online or ArcGIS Enterprise organization is impossible, so the entire ArcGIS for Power BI visualization is not supported.
Use one of the supported environments to leverage ArcGIS for Power BI. For more information, refer to Microsoft: Considerations and limitations.