fix(drive-abci)!: masternode identities unique keys

[QuantumExplorer]

Issue being fixed or feature implemented

Masternode operator keys were being added to the unique tree lookup. If a masternode would go offline and then come back online then the key would be re-inserted as unique and the system would break.

What was done?

Masternode operator keys are no longer considered unique in the system. Also if a unique operator key was already taken by an identity it can still be used by a masternode as to prevent users from breaking Platform.

How Has This Been Tested?

Ran tests.

Breaking Changes

This is a breaking chance as masternode operator keys are no longer added to the unique tree lookup.

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have added "!" to the title and described breaking changes in the corresponding section if my code contains any
• I have made corresponding changes to the documentation if needed

For repository code-owners and collaborators only

• I have assigned this pull request to a milestone

[shumkov]

Good catch! We probably could make it a little bit better by moving masternode-specific logic outside of the generic add_new_idenity method using a separate Drive operation or perform the re-enable logic (if the tree already exists) in the masternode identities module before we actually add a new identity.