fix: prevent error with undefined/null headers entries

Author: farfromrefug

src/https/request.android.ts

@@ -472,7 +472,11 @@ export function createRequest(opts: HttpsRequestOptions, useLegacy: boolean = tr
     request.url(opts.url);
 
     if (opts.headers) {
-        Object.keys(opts.headers).forEach((key) => request.addHeader(key, opts.headers[key] as any));
+        Object.keys(opts.headers).forEach((key) => {
+            if (opts.headers[key]) {
+                request.addHeader(key, opts.headers[key] as any);
+            }
+        });
     }
 
     if (opts.cachePolicy) {

src/https/request.ios.ts

@@ -370,7 +370,11 @@ export function createRequest(opts: HttpsRequestOptions, useLegacy: boolean = tr
     if (heads) {
         headers = NSMutableDictionary.dictionary();
         Object.keys(heads).forEach(
-            (key) => headers.setValueForKey(heads[key], key)
+            (key) => {
+                if (heads[key]) {
+                    headers.setValueForKey(heads[key], key);
+                }
+            }
             // manager.requestSerializer.setValueForHTTPHeaderField(
             //     heads[key] as any,
             //     key