Get account balance

Bad Request. Possible error codes:

HTTP status	Code / title	Description
400	`ValidationError` / `INCORRECT_INPUT_DATA`	One or more request parameters are missing, invalid or used in an invalid combination.
400	`DomainError` / `INVALID_ACCOUNT`	The requested account and currency pair was not found or is not available to the client.
400	`DomainError` / `USER_IS_DELETED`	The user related to the API integration does not exist or is deleted.
400	`DomainError` / `USER_IS_NOT_ACTIVE`	The user related to the API integration is not active.
400	`DomainError` / `USER_IS_BLOCKED`	The user related to the API integration is blocked.

200Successful response with account balance information.