Avoid: Undefined index: value in app/code/Magento/Catalog/Controller/Adminhtml/Product/Attribute/Validate.php on line 157 in Ajax return

[mhauri]

When saving an Attribute and the array $options doesn't contain a key named 'value' or 'delete' it will return a Notice Warning instead of the expected ajax result in admin/catalog/product_attribute/validate/attribute_id/XXX/

Description

This PR will check if the keys 'value' and 'delete' are set.

Fixed Issues (if relevant)

1. Cannot save attribute #8202: Cannot save attribute
2. Visibility save attribute error #8271: Visibility save attribute error

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-cicd2]

All committers have signed the CLA.

[adragus-inviqa]

Hi. Appreciate the time, but there's a small suggestion I'd like to make. The style should be:

if (foo &&
    bar &&
    baz) {
//  ...
}

For the life of me I can't find the style guide (I was looking in PSR-2), but I'm sure I can find it somewhere. 😬

[magento-team]

@mhauri Thank you for the contribution