Fixing disabled styling of search submit button.

[linuspahl]

Description

The disabled styling for the search submit button is currently missing.

The reason:

The styling has been applied in the SearchButton by setting the disabled class, instead of the disabled prop for the button., We did this because we still want to trigger the onClick event, when the button is disabled to show a dialog which explains why the button is disable. The onClick event is usually not being triggered when a button is disabled.

The problem is that the button disabled styling is no longer applied via the CSS class in the Button component. I assume since we migrate from react-bootstrap to Mantine.

This PR implements a cleaner solution to achieve the desired behavior. We are extending the Button component with a prop that allows to trigger the onClick event when the button is disabled.

/prd Graylog2/graylog-plugin-enterprise#14797,Graylog2/e2e-tests#1682
/nocl - fixes a small visual regression

[maxiadlovskii]

@linuspahl, we have disabled styles while just typing the query. Is that desirable behaviour?

[linuspahl]

Yes, because you can't submit while the query validation is happening.

[maxiadlovskii]

@linuspahl Ok. My main concern was that the button is blinking while you are typing