fix (generator): let generated client import types using TypeScript's import type

[kevin-dp]

This PR fixes #707 by explicitly importing types using import type instead of just import.

[thruflo]

Great 👍

Can I just sanity check: are there any other places in the code where we should fix this to make imports work for a Svelte developer?

I.e.: if they're importing other types exposed by the main typescript client library?

[kevin-dp]

Great 👍

Can I just sanity check: are there any other places in the code where we should fix this to make imports work for a Svelte developer?

I.e.: if they're importing other types exposed by the main typescript client library?

This is a concern of the one that is importing, i.e. only a problem in the project that is using Svelte (not internally in our electric-sql package). Therefore, I believe those imports are under the control of the application developer and it's their responsibility to import types using import type.