[SSF-169] backend logic to return required actions for FM

[amywng]

ℹ️ Issue

Closes SSF-169

📝 Description

• updated getFMDonations in `manufacturers.service.ts
  • to take in current request user id and check that it matches the manufacturer representative id
  • return only matched donations
  • for each donation, return associated pending orders (where orders have at least one allocation tied to a donation item from the donation
  • for each donation, return relevant donation items (that are used in any associated order and detailsConfirmed is false)
• added DonationDetailsDto for return type
• updated controller and service tests

✔️ Verification

verified tests pass and tested call in postman

[Juwang110]

Minor things but looks great!

[Yurika-Kan]

coolington~

one design note included about keeping previous implementation logic (donations of all statuses) & then adding the matched logic

• jest tests
• postman tested

[Yurika-Kan]

we need to return a FM's donations -all statuses- for this page and also get complete required actions for only matched donations, so i'd suggest filtering for matched & returning the hefty payload

[Yurika-Kan]

design choice of:

• 2 endpoints (all status donations + all matched donations) - separation of concerns & conditionally controlling lighter vs heavier payload BUT frontend has to manage 2 endpoints
• 1 endpoint + conditional rendering for matched donations: one main endpoint BUT more service logic & heavier payload

leaning towards the 1 endpoint since this page with donations statuses will be frequently changing. lmk your thoughts!