[types] remove incorrect overload

Author: ljharb

index.d.ts

@@ -1,5 +1,4 @@
 declare function arrayBufferByteLength(buffer: ArrayBuffer): number;
-declare function arrayBufferByteLength(buffer: ArrayBuffer): 'AUTO';
 declare function arrayBufferByteLength(buffer: unknown): typeof NaN;
 
 export = arrayBufferByteLength;