Disable specific sidebar actions on search page, when search page has errors.

## What?

## Why?

With https://github.com/Graylog2/graylog2-server/pull/10798 we introduced the `hasError` flag for the search page. When opening a search page, which has errors we are no longer displaying the search results.

In this case we should disable some actions, because they do not or should not have an effect:
- creating a widget
- field actions in sidebar fields list.

We could share the `hasError` state by using a context. In this case we should use the state to disable the dashboard save action. We are currently disabling these action based on `searchMetadata.undeclared.size`.

## Your Environment

* Graylog Version: current development version for 4.1