Changes to Add a line item to a claim

added the new optional request property id

the id response's property type changed from integer to string, and format from int64 to uuid for status 201

for the path request parameter claimId, the type was generalized from integer to string, and format from int64 to uuid

removed the success response with the status 204

added the non-success response with the status 400

removed the non-success response with the status 404

added the success response with the status 201

endpoint added