Add collatorSelection Calls To Type Definitions

[ProfMoo]

As a user of the collatorSelection RPC endpoints, I want to be able to utilize TypeScript's type system while developing against these endpoint.

For example, here is my code:

const currentCandidates = await api.query.collatorSelection.candidates();

I believe that the additional types would need to be added into this file: https://github.com/AcalaNetwork/acala.js/blob/905a7b9691be462e4710b4a8ec08ca698d06f5bb/packages/types/src/interfaces/augment-api-tx.ts