feat!: respond with already exists grpc error

[shumkov]

Issue being fixed or feature implemented

To ease error handling for clients, DAPI should respond with already exists gRPC errors in appropriate cases instead of a more general invalid argument.

What was done?

• Respond with already exists error in broadcastStateTransition endpoint
• Respond with already exists error in broadcastTransaction endpoint

How Has This Been Tested?

With unit tests

Breaking Changes

• Already exists error responded instead of invalid argument if transaction or state transition already exists in chains

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 made corresponding changes to the documentation

For repository code-owners and collaborators only

• I have assigned this pull request to a milestone