[FEATURE] add `current_locked_balance` to token holder collection API response

[purplesmoke05]

Is your feature request related to a problem? Please describe.

• In current implementation, following endpoint returns only balance at given block_number.
  • GET: /token/holders/{token_address}/collection/{list_id}
• There are some needs to get current_locked_balance at the time of the API request.

Describe the solution you'd like

• Add current_locked_balance to token holder collection API response data.

[purplesmoke05]

Close to be developed in the following Issue. https://github.com/BoostryJP/ibet-Prime/issues/471