Method MobileElement.getAttribute() throws NoSuchElementException

Description

Call to element.getAttribute("MISSING_ATTR") throws NoSuchElementException in Appium, but returns null in Chrome, Firefox and others webdrivers. I believe Appium should also return null instead of throwing exception. It's a totally valid case when I want to log some attributes of the element. I don't want to write multiple try/catch blocks to do it.

Environment

• io.appium:java-client:7.1.0
• Appium server version: 1.7.2

Code To Reproduce Issue

assertNull(appiumDriver.findElement(By.id("result")).getAttribute("FOOBAR"));

Causes the exception:
https://gist.github.com/asolntsev/36ad1bdfce253cb5ba8210d1c2f909e0

Link to Appium logs

[debug] [AndroidBootstrap] [BOOTSTRAP LOG] [debug] Got data from client: {"cmd":"action","action":"element:getAttribute","params":{"attribute":"class","elementId":"5"}}
[debug] [AndroidBootstrap] [BOOTSTRAP LOG] [debug] Returning result: {"status":7,"value":"This element does not have the 'class' attribute"}

Start by tracing the Java client's MobileElement.getAttribute() path and compare its handling with the WebDriver behavior described in the issue. Reproduce the call using the provided assertNull example and add or update a regression test so a missing attribute returns null rather than NoSuchElementException.