Expand all twice in expandrow hangs the page

[Benn]

Prerequisites

• I have searched for similar issues in both open and closed tickets and cannot find a duplicate.
• The issue still exists against the latest master branch of yii2-grid.
• This is not an usage question. I confirm having gone through and read the documentation and demos.
• This is not a general programming / coding question. (Those should be directed to the webtips Q & A forum).
• I have attempted to find the simplest possible steps to reproduce the issue.
• I have included a failing test as a pull request (Optional).

Steps to reproduce the issue

1. Go to the demo page (https://demos.krajee.com/grid-demo)
2. Click the + button to expand, and click the minus butto to colapse
3. Click the + button again

Expected behavior and actual behavior

When I follow those steps, I see the spinner which keeps turning, the rows do not expand. Single rows do still expand properly

I was expecting all rows to expand again.

Environment

Browsers

• Google Chrome
• Mozilla Firefox
• Internet Explorer
• Safari

Operating System

• Windows
• Mac OS X
• Linux
• Mobile

Libraries

• jQuery version: see demo
• yii2-grid version: see demo

Isolating the problem

• This bug happens on the demos page
• The bug happens consistently across all tested browsers
• This bug happens when using yii2-grid without other plugins.

[kartik-v]

Fixed and resolved via above commit.