Fix "Send by enter" on Windows

Apparently on windows `Qt.inputMethod.visible` is always true when an input method is installed. Also on windows even after removing the check enter is still consumed by the input method, not nheko.

resources/qml/MessageInput.qml

@@ -223,7 +223,7 @@ Rectangle {
                                 return;
                             }
                         }
-                        if (!Qt.inputMethod.visible) {
+                        if (!Qt.inputMethod.visible || Qt.platform.os === "windows") {
                             room.input.send();
                             event.accepted = true;
                         }