Added missing completed proposal queries to approval-single

[NoahSaso]

The dao-pre-propose-approval-single contract does not store pending proposals once they have been approved or rejected. This makes it impossible to retrieve past decisions and connect approval proposals used in dao-pre-propose-approver to existing proposals.

This PR adds queries to check whether or not a given approval ID is pending, and allows querying completed proposals. If approved, it also includes the created proposal ID. It also adds a query to get the completed pre-propose ID from the created proposal ID.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## development #767 +/- ## ============================================== Coverage ? 96.27% ============================================== Files ? 203 Lines ? 50289 Branches ? 0 ============================================== Hits ? 48414 Misses ? 1875 Partials ? 0 ```

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