Fix `.d.ts` extension usage in type declaration exports

[MajorLift]

We should set up ts-bridge to generate and expose unambiguous .d.cts and .d.mts type declarations only.

Using .d.ts causes issues in downstream projects that have their moduleResolution option set to Node16 or NodeNext.

e.g.

error TS2307: Cannot find module '@metamask/providers' or its corresponding type declarations.

https://github.com/MetaMask/core/actions/runs/9668650800/job/26673339021?pr=3645

[mcmire]

@MajorLift I believe that this is one of the design goals of ts-bridge and so it does this by default. If you view the latest version of @metamask/utils you can see separate .d.cts and .d.mts files: https://npmfs.com/package/@metamask/utils/8.5.0/dist/