fix: use ToLowerInvariant in clipboard to follow invariant culture (#920)

* fix: use ToUpper in clipboard

* Update AppiumCommandExecutionHelper.cs

Author: KazuCocoa

src/Appium.Net/Appium/AppiumCommandExecutionHelper.cs

@@ -85,6 +85,8 @@ public static bool IsKeyboardShown(IExecuteMethod executeMethod)
         public static void SetClipboard(IExecuteMethod executeMethod, ClipboardContentType clipboardContentType,
             string base64Content)
         {
+            var contentType = clipboardContentType.ToString().ToLowerInvariant();
+
             switch (clipboardContentType)
             {
                 case ClipboardContentType.Image:
@@ -97,18 +99,19 @@ public static void SetClipboard(IExecuteMethod executeMethod, ClipboardContentTy
 
                     executeMethod.Execute(AppiumDriverCommand.SetClipboard,
                         PrepareArguments(new[] {"content", "contentType", "label"},
-                            new object[] {base64Content, clipboardContentType.ToString().ToLower(), null}));
+                            new object[] {base64Content, contentType, null}));
                     break;
                 default:
                     executeMethod.Execute(AppiumDriverCommand.SetClipboard,
                         PrepareArguments(new[] {"content", "contentType", "label"},
-                            new object[] {base64Content, clipboardContentType.ToString().ToLower(), null}));
+                            new object[] {base64Content, contentType, null}));
                     break;
             }
         }
 
         public static string GetClipboard(IExecuteMethod executeMethod, ClipboardContentType clipboardContentType)
         {
+            var contentType = clipboardContentType.ToString().ToLowerInvariant();
             switch (clipboardContentType)
             {
                 case ClipboardContentType.Image:
@@ -118,15 +121,12 @@ public static string GetClipboard(IExecuteMethod executeMethod, ClipboardContent
                         throw new NotImplementedException(
                             $"Android only supports contentType: {nameof(ClipboardContentType.PlainText)}");
                     }
-
-                    return (string) executeMethod.Execute(AppiumDriverCommand.GetClipboard,
-                        PrepareArgument("contentType", clipboardContentType.ToString().ToLower())).Value;
-                case ClipboardContentType.PlainText:
                     return (string) executeMethod.Execute(AppiumDriverCommand.GetClipboard,
-                        PrepareArgument("contentType", clipboardContentType.ToString().ToLower())).Value;
+                        PrepareArgument("contentType", contentType)).Value;
                 default:
+                    // including ClipboardContentType.PlainText
                     return (string) executeMethod.Execute(AppiumDriverCommand.GetClipboard,
-                        PrepareArgument("contentType", clipboardContentType.ToString().ToLower())).Value;
+                        PrepareArgument("contentType", contentType)).Value;
             }
         }
 
@@ -144,7 +144,7 @@ public static string SetClipboardText(IExecuteMethod executeMethod, string textC
                     new object[]
                     {
                         Convert.ToBase64String(encodedStringContentBytes),
-                        ClipboardContentType.PlainText.ToString().ToLower(), label
+                        ClipboardContentType.PlainText.ToString().ToLowerInvariant(), label
                     })).Value;
         }
 
@@ -214,4 +214,4 @@ internal static Dictionary<string, object> PrepareArguments(string[] names, obje
             return parameterBuilder;
         }
     }
-}
+}