Gets or sets the text part position properties for the floating part of the callout text.
This contains the relative positioning information, as well as split offset indicating
the extent to which the callout part will mask the callout outline, and whether or not the
part should be boxed in by the overall callout, or not. The floating part is anchored below
the bottom text part. If there is no bottom text part it is anchored below the middle text part
plus margins.
Target Platforms: Windows 11, Windows 10
ArcGIS Pro version: 3.0 or higher.