fix: dont assign type double, assert it's imported

src/main.ts

@@ -1,12 +1,5 @@
-import type { getNetlifyGlobal } from '@netlify/serverless-functions-api'
-
 export { builder } from './lib/builder.js'
 export { purgeCache } from './lib/purge_cache.js'
 export { schedule } from './lib/schedule.js'
 export { stream } from './lib/stream.js'
 export * from './function/index.js'
-
-// Ambient type declarations
-declare global {
-  const Netlify: ReturnType<typeof getNetlifyGlobal>
-}

test/types/Netlify_Global.test-d.ts

@@ -0,0 +1,6 @@
+import { expectAssignable } from 'tsd'
+
+// eslint-disable-next-line import/no-unassigned-import
+import '../../src/main.js'
+
+expectAssignable<{ env: unknown }>(Netlify)