When column is set to be readOnly the 'Clear column' option should be disabled.

[AMBudnik]

Description

When column is set to be readOnly the Clear column option should be disabled.

Steps to reproduce

1. Go to column A and make it readOnly via dropdownMenu

Result
You are able to choose the Clear column option but it won't work (content is readOnly).

Expected result
You are NOT able to choose the Clear column option.

Demo

https://jsfiddle.net/cpv9eLzx/ 7.4.2

Your environment

• Handsontable version: 7.4.2
• Browser Name and version: Chrome 80
• Operating System: macOS Catalina

[AMBudnik]

Works the same in v8.2.0 https://jsfiddle.net/handsoncode/wyz79scj/