bug: 'ssrServerServer' implicitly has type 'any'#188

### Describe the Bug When I build the `/functions` directory in a project that is configured to use typescript and use the recommended CLI output I face type issues: ``` $ yarn --cwd ./functions run build $ tsc src/index.ts:6:5 - error TS7034: Variable 'ssrServerServer' implicitly has type 'any' in some locations where its type cannot be determined. 6 let ssrServerServer; ~~~~~~~~~~~~~~~ src/index.ts:8:7 - error TS7005: Variable 'ssrServerServer' implicitly has an 'any' type. 8 if (!ssrServerServer) { ~~~~~~~~~~~~~~~ Found 2 errors in the same file, starting at: src/index.ts: ``` This is due to the fact that the default CLI code is doing a few unsafe things (for one thing it's referencing a file that does not exist until after compile!). Even if I do move the file over it's a js file without type definitions. ### Steps to Reproduce 1. Create a typescript sveltekit project 2. Set up firebase init for `functions` with typescript enabled 3. Run build; follow CLI insertion instructions 4. Build the functions ### Expected Behaviour I would expect the inserted `ssrServer` code to either (A) be written in TypeScript or (B) include type definitions. ### svelte-adapter-firebase version 0.14.4 ### sveltejs/kit version 1.0.0-next.488