update `LocalKeyManager` Key IDs to match convention set in `web5-js`

[KendallWeihe]

Unclear to me what the concrete intent is with this ticket

Sharing these for reference

• https://github.com/TBD54566975/web5-js/blob/main/packages/crypto/src/local-key-manager.ts
• https://github.com/TBD54566975/web5-js/blob/main/packages/crypto/src/types/identifier.ts

[mistermoe]

@KendallWeihe js uses urns as key ids. @frankhinek can you provide an example key id?