added pattern null check, update docs, add test (#518)

Author: SecondeJK

README.md

@@ -921,7 +921,7 @@ $filter
     ->setPattern(234)
     ->setSearchPattern(\Vonage\Numbers\Filter\OwnedNumbers::SEARCH_PATTERN_CONTAINS)
 ;
-$response = $client->numbers()->searchOwned($filter);
+$response = $client->numbers()->searchOwned(null, $filter);
 ```
 
 `has_application`:

src/Numbers/Filter/OwnedNumbers.php

@@ -38,7 +38,7 @@ class OwnedNumbers implements FilterInterface
 
     protected int $pageIndex = 1;
 
-    protected string $pattern;
+    protected ?string $pattern = null;
 
     protected int $searchPattern = 0;
 

test/Numbers/ClientTest.php

@@ -361,6 +361,27 @@ public function testPurchaseNumberWithNumberObject(): void
         // If there's no exception thrown, everything is fine!
     }
 
+    public function testSearchOwnedNumbersWithFilter(): void
+    {
+        $this->vonageClient->send(Argument::that(function (RequestInterface $request) {
+            $uri = $request->getUri();
+            $uriString = $uri->__toString();
+            $this->assertEquals(
+                'https://rest.nexmo.com/account/numbers?size=10&index=1&application_id=66c04cea-68b2-45e4-9061-3fd847d627b8&page_index=1',
+                $uriString
+            );
+
+            $this->assertEquals('GET', $request->getMethod());
+
+            return true;
+        }))->willReturn($this->getResponse('owned-numbers'));
+
+        $filter = new \Vonage\Numbers\Filter\OwnedNumbers();
+        $filter->setApplicationId("66c04cea-68b2-45e4-9061-3fd847d627b8");
+
+        $response = $this->numberClient->searchOwned(null, $filter);
+    }
+
     public function testPurchaseNumberWithNumberAndCountry(): void
     {
         // When providing a number string, the first thing that happens is a GET request to fetch number details

test/Numbers/responses/owned-numbers.json

@@ -0,0 +1,16 @@
+{
+  "count": 1234,
+  "numbers": [
+    {
+      "country": "GB",
+      "msisdn": "447700900000",
+      "type": "mobile-lvn",
+      "cost": "1.25",
+      "features": [
+        "VOICE",
+        "SMS",
+        "MMS"
+      ]
+    }
+  ]
+}