feat: encapsulate data pdf formatting

[kevin9foong]

Problem

Pdf rendering requires transformation of data to a specific format, which is duplicated across mrf and storage mode. This duplication can be removed.

Solution

Encapsulate the pdf rendering to within the pdf generation function itself, reducing the chances of inconsistencies in pdf data format across form modes.

Breaking Changes

No - this PR is backwards compatible

Tests

TC1: PDF copy generated correctly for MRF with signature field

• Create an MRF with signature field and a bunch of other fields (table, short text etc)
• Add an email field with respondent copy PDF.
• Submit the form.
• Assert that the respondent email is received with correct PDF details (note the date format, form name, submission id and fields and their answers are correct)

TC1: PDF copy generated correctly for Storage mode with signature field

• Create an storage mode with signature field and a bunch of other fields (table, short text etc)
• Add an email field with respondent copy PDF.
• Submit the form.
• Assert that the respondent email is received with correct PDF details (note the date format, form name, submission id and fields and their answers are correct)