Add missing query to dao-pre-propose-approver

[NoahSaso]

The dao-pre-propose-approver contract does not currently provide any query to determine which pre-propose ID corresponds with a given proposal. In other words, you cannot check which pending proposal an approval proposal was made for.

This PR adds a query PendingProposalIdForApprovalProposalId which takes the id of the approval proposal being voted on by the approval DAO and returns the id of the pending proposal in the dao-pre-propose-single contract on the DAO waiting for proposal approval.

[codecov[bot]]

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```diff @@ Coverage Diff @@ ## development #766 +/- ## ============================================== Coverage ? 96.26% ============================================== Files ? 203 Lines ? 50093 Branches ? 0 ============================================== Hits ? 48221 Misses ? 1872 Partials ? 0 ```

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