Skip file upload tests on Saucelabs, because W3C protocol does not support remote file upload

See w3c/webdriver#1355

Author: OndraM

lib/Remote/RemoteWebElement.php

@@ -358,6 +358,7 @@ public function isSelected()
     public function sendKeys($value)
     {
         $local_file = $this->fileDetector->getLocalFile($value);
+
         if ($local_file === null) {
             if ($this->isW3cCompliant) {
                 $params = [
@@ -370,22 +371,18 @@ public function sendKeys($value)
                     ':id' => $this->id,
                 ];
             }
-
-            $this->executor->execute(DriverCommand::SEND_KEYS_TO_ELEMENT, $params);
-
-            return $this;
-        }
-
-        if ($this->isW3cCompliant) {
-            $params = [
-                'text' => $local_file,
-                ':id' => $this->id,
-            ];
         } else {
-            $params = [
-                'value' => WebDriverKeys::encode($this->upload($local_file)),
-                ':id' => $this->id,
-            ];
+            if ($this->isW3cCompliant) {
+                $params = [
+                    'text' => $local_file,
+                    ':id' => $this->id,
+                ];
+            } else {
+                $params = [
+                    'value' => WebDriverKeys::encode($this->upload($local_file)),
+                    ':id' => $this->id,
+                ];
+            }
         }
 
         $this->executor->execute(DriverCommand::SEND_KEYS_TO_ELEMENT, $params);

tests/functional/FileUploadTest.php

@@ -26,6 +26,8 @@ class FileUploadTest extends WebDriverTestCase
     /**
      * @group exclude-edge
      * https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/6052385/
+     * @group exclude-saucelabs
+     * W3C protocol does not support remote file upload: https://github.com/w3c/webdriver/issues/1355
      */
     public function testShouldUploadAFile()
     {