Add missing accounts and balances REST APIs to acceptance tests

[ashumahajan]

Problem

We're missing acceptance test coverage for some mirror node REST APIs.

Solution

Based on #4051 , add below apis coverage to acceptance tests
/api/v1/accounts - List all accounts
/api/v1/accounts/{id}/rewards - Staking rewards
/api/v1/balances - Account balances endpoint

Alternatives

No response

[ashumahajan]

Parent #11807