Missing tests in sidechain CCU update command

[mitsuaki-u]

Expected behavior

Should be complete test coverage

Actual behavior

Missing tests:

verify:

• Update params validation test to use context creation utility function and check for throw
• if len(certificateBytes) == 0 and ccu.params.inboxUpdate is empty should throw
• if chainAccount(ccu.params.sendingChainID) does not exist should throw
• if len(validatorsUpdate.blsKeysUpdate) > 0 or len(validatorsUpdate.bftWeightsUpdate) > 0 or validatorsUpdate.bftWeightsUpdateBitmap != EMPTY_BYTES or ccu.params.certificateThreshold != validators(ccu.params.sendingChainID).certificateThreshold should call veriftValidatorsUpdate(ccu)

execute:

• Update the context to indicate that now we stop the CCM processing.
  ctx.ccmProcessing = False
  (double check if this is done differently in the code through events or another method)

Steps to reproduce

Which version(s) does this affect? (Environment, OS, etc...)

development

[sitetester]

This issue is mostly superseded by recent changes in #8840 when verifyCommon method was updated in relevant LIP.

Also since LIP 53 has updated lately, those changes are planning to be addressed in #9009