Context

Pallet: identityManagement[Mock]

Consider the following scenario

1. A user request identityManagement.linkIdentity('Twitter', 'my-handle') -> ChallengeCodeGenerated event is emitted.
2. User request again identityManagement.linkIdentity('Twitter', 'my-handle').

Received:
The transaction fails with IdentityAlreadyExist.

Desired:
On point 2, generate a new challenge code. i.e., a ChallengeCodeGenerated event is emitted.

How this useful

• Better Developer Experience: It makes testing easier as you can re-use the same web_type and handle to get the same results while not minding spending tokens.
• Better User Experience: Users won't need to pay fees for unlinkIdentity in case they lose their challengeCode, and retrieving through an indexer is not an option for them.
• Better Consumer Experience: as a dApp developer, I would like to leave ChallengeCodes retrieval from an archive node for later.