pass custom close icon in options

[jiblett1000]

Detailed Description

Hello, I see in the documentation that you can create a custom close button component. However, it would be nice to just be able to set a custom close icon without creating a custom component. For example, this can currently be done for the different notification types (error, warning, etc). So, a similar option for the close button would be great.

Context

I think the above about sums it up.

Possible Implementation