Bulk updating of submissions

Where <field_to_update_n> is a string and should be an existing XML field value of the submissions. If <field_to_update_n> is part of a group or nested group, the field must follow the group hierarchy structure, i.e.:

If the field is within a group called group_1, the field name is question_1 and the new value is new value, the payload should contain an item with the following structure:

"group_1/question_1": "new value"

Similarly, if there are N nested groups, the structure will be:

"group_1/sub_group_1/.../sub_group_n/question_1": "new value"