add unit test to cover `CandidateActivate` methods

[saitofun]

What would you like to be added

Add unit test for functions of CandidateActivate

in file action/candidate_activate.go

• [ ] Add tests to cover #L26
• [ ] Add tests to cover #L29-L30
• [ ] Add tests to cover #L34-L36
• [ ] Add tests to cover #L39-L40
• [ ] Add tests to cover #L44-L46
• [ ] Add tests to cover #L51-L53
• [ ] Add tests to cover #L55-L56
• [ ] Add tests to cover #L60-L68