[#1994] Remove deprecated assert functions.

Description
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Implement specialized `assertError` and `assertErrorID` that will check for a valid error type (ServerError and siblings) and data serialization.

This renders `assertExceptionID` and `assertExceptionData` deprecated.

Changes
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I've removed the deprecated functions.

Updated to latest brink release: `0.39.2`.

How to test
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reviewers @adiroiban 

Check that the changes make sense.