User_id check in Patch item is useless

[nichyjt]

Two useless checks:

1. Backend Microservice
   The backend requires that User_id be passed as a URL parameter. This is useless a the request body itself should contain User_id, implying that the item belongs to the LOST collection of items
2. Item Microservice
   User_id is checked via URL param - but this is useless. The User_id existence should be checked via the request body iteself

[nichyjt]

Re-labelled this to enhancement for now because this is lower priority and not breaking. This is a good-to-have optimization. Further, URL depreciation can be done without breaking the frontend logic.