Entity-BN - update to ensure sorting for firm legal name is correct

[argush3]

The logic for retrieving the firm legal name does not take into account of sorting the person name or organization name for registrations. COLIN did this. The logic change should be pretty minimal from an initial look at the code.

Change of registrations logic also needs to be updated to sort by party name correctly and only return the first two names.

TODOs

• [ ] Update _get_firm_legal_name to sort names correctly when retrieving firm legal name.
• [ ] Update change_name to sort names correctly when picking up a name change and also to only return first 2 names.
• [ ] Update tests as required

Below are some ideas as to how updates can be made for firm legal name related code. Note that the code has not been tested.

Potential fix for registration.py

Potential fix for change_of_registration.py