[#652] Add dummy value for getAlias in MorleyOnlyRpcM

Description

Problem: Recently (at #875 (closed)) some functionality was presented. The problem is that there are a bug. getAlias is called at tx submission function for logging purposes, so an exception will be raised if someone try to send transaction. This situation contradicts the main goal of #875 (closed).

Solution: Return dummy value in getAlias.

Related issue(s)

Related to #652

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