Add row to calculate coordinates of additional entity

[Sujanadh]

Description:

This feature introduces functionality to calculate and retrieve the coordinates of an additional entity selected in a survey form.

• Adds a new calculate row that retrieves the coordinates of the selected entity. This is done using an instance reference for the entity and retrieves the geometry field using the following XPath expression:

"calculation": [f"instance('{entity_name}')/root/item[name=${entity_name}]/geometry"]

Issue:

• Unable to view the geometry of additional features in the map in submission detail due to missing coordinates.
• Visualise additional features on submission details page fmtm#1882
• Fixes loading issue of additional entities in odk collect due to unmatch name with additional features uploaded to odk central; removed code that removes trailing 's' letter from the entity name to make it singular.

[spwoodcock]

It's quite nice having the field in code like this.

It's verbose, but we can then use source control.

Do you think we should remove the mandatory fields xls file and build the dataframe here instead?

[Sujanadh]

I think we tried that initially when we were writing this function to append fields. But it looked so messy and complex so we decided to use a file instead, updating the form seemed easier during that time.