Fix URLSearchParams.keys() returning only unique keys

The WHATWG URL spec states that URLSearchParams.keys() must yield one
entry per name-value pair, meaning duplicate names appear multiple times.

The previous implementation returned Map.keys() directly, which yields each
key only once regardless of how many values are stored under it. This caused
keys() to be inconsistent with values() and entries(), both of which already
handle duplicates correctly.

Updated keys() to use a generator that yields each key once per associated
value, matching the approach already used by values() and entries().

Test plan: Added a test asserting that keys() on URLSearchParams with
duplicate key entries ('key1', 'key1', 'key2') returns all three names.

Changelog:
[General] [Fixed] - Fix URLSearchParams.keys() returning only unique keys instead of all name-value pair names

Author: nedunchezhiyan-fin

packages/react-native/Libraries/Blob/URLSearchParams.js

@@ -77,7 +77,14 @@ export class URLSearchParams {
   }
 
   keys(): Iterator<string> {
-    return this._searchParams.keys();
+    function* generateKeys(params: Map<string, string[]>): Iterator<string> {
+      for (const [key, values] of params) {
+        for (let i = 0; i < values.length; i++) {
+          yield key;
+        }
+      }
+    }
+    return generateKeys(this._searchParams);
   }
 
   values(): Iterator<string> {

packages/react-native/Libraries/Blob/__tests__/URL-test.js

@@ -114,6 +114,10 @@ describe('URL', function () {
     expect(paramsFromArray.getAll('key1')).toEqual(['value1', 'value2']);
     expect(paramsFromArray.get('key2')).toBe('value3');
 
+    // keys() should yield one entry per name-value pair, including duplicates
+    const keysArray = Array.from(paramsFromArray.keys());
+    expect(keysArray).toEqual(['key1', 'key1', 'key2']);
+
     // Manipulating existing search params in the URL
     const urlParams = url.searchParams;
     expect(urlParams.get('query')).toBe('testQuery');