Notification close icon color on hover is not customizable

[jbe456]

• I have searched the issues of this repository and believe that this is not a duplicate.

Version

3.4.3

Environment

N/A

Reproduction link

https://github.com/ant-design/ant-design/blob/3.4.3/components/notification/style/index.less#L121

Steps to reproduce

While it is possible to customize the close icon color through the variable @text-color-secondary, the hover color is hardcoded to #404040
Cf https://github.com/ant-design/ant-design/blob/3.4.3/components/notification/style/index.less#L121

What is expected?

To be able to configure the close icon hover color for notifications, the same way it can be done with regular close icon color.

What is actually happening?

We can't