HTTP/TS: Fix response type checks throwing on certain inputs (#788)

## Usage and product changes

In the HTTP/TS driver, `isApiErrorResponse` and `isOkResponse` should
never throw errors anymore for any input.

## Motivation

Although their input is theoretically restricted, in practice errors in
TypeScript usually have the `any` type when they're thrown from HTTP
libraries such as `fetch`.

## Implementation

Check that the input is actually an object before scanning it

Author: alexjpwalker

http-ts/BUILD

@@ -106,6 +106,7 @@ checkstyle_test(
         "tool/**/*",
     ]),
     exclude = glob([
+        ".npmrc",
         "**/*.json",
         "**/*.md",
         "pnpm-lock.yaml",

http-ts/src/response.ts

@@ -119,9 +119,9 @@ export function isApiError(err: any): err is ApiError {
 export type ApiResponse<OK_RES = {} | null> = ApiOkResponse<OK_RES> | ApiErrorResponse;
 
 export function isOkResponse<OK_RES>(res: ApiResponse<OK_RES>): res is ApiOkResponse<OK_RES> {
-    return "ok" in res;
+    return typeof res === "object" && "ok" in res;
 }
 
 export function isApiErrorResponse(res: ApiResponse): res is ApiErrorResponse {
-    return "err" in res;
+    return typeof res === "object" && "err" in res;
 }