fix(functions): update typescript templates to support ts 6 and fix linting (#10939)

### Description
Updates the TypeScript Cloud Functions template to support TypeScript 6 and resolves out-of-the-box linting errors/warnings in newly initialized projects.

Specifically:
- Upgrades `@typescript-eslint/eslint-plugin` and `@typescript-eslint/parser` to `^8.0.0` and `eslint` to `^8.57.0` in package templates to support TypeScript 6.
- Adds `allowJs: true` to `tsconfig.dev.json` to resolve the `TS18003: No inputs were found` error when linting config files (like `.eslintrc.js`).
- Comments out unused imports (`onRequest`, `logger`) in `index.ts` by default to avoid unused variable warnings.
- Fixes spacing in `setGlobalOptions` in `index.ts` to match standard ESLint spacing rules.

### Scenarios Tested
- Initialized a new project using the updated templates and verified that `npm run lint` passes successfully without any warnings or errors.
- Verified that `firebase deploy functions` runs successfully without warnings or errors.

### Sample Commands
- `firebase init`

TAG=agy
CONV=e55af4de-d0de-4b48-841c-43e04476766c