Add "Context Menu" key to keyboard actions

[wassim-devel]

There are several special keys defined in the specification; however, the “Context Menu” key — which allows opening a context menu without using a mouse — is missing.

https://www.w3.org/TR/webdriver/#keyboard-actions

The absence of this key makes it impossible to fully test keyboard navigation in tools like Selenium, especially when an application includes elements that require right-click interaction.

Some users have disabilities that prevent them from using a mouse, so I'd say it's important to support testing accessibility features through keyboard-only navigation