Always-on Search field

When "searchOpen" option is set to true, is it possible to truly replace the title with the search field (title is not in use in my use case).
Because when the "viewColumn" or "filter" pop-over are opened, search field will be hidden, and it will have to turn back on by clicking the search icon again, which can be annoying for the users.

## Expected Behavior

search field always-on.

## Current Behavior

search field will be hidden when other action icon (filter, view column) are clicked.

## Steps to Reproduce (for bugs)
code sandbox
https://codesandbox.io/embed/muidatatables-custom-toolbar-q078r?fontsize=14&hidenavigation=1&theme=dark

| Tech | Version |
|--------------|---------|
| Material-UI | 4.6.1 |
| MUI-datatables | 2.12.4 |
| React | 16.9.0 |
| browser | Chrome |

Start with the linked CodeSandbox reproduction and inspect how the toolbar search field behaves when the filter or view-column popovers open. Reproduce the field being hidden, then trace the corresponding toolbar entry point in the repository. Done means searchOpen=true keeps the search field visible while those actions are used.

Written by the indexing model from the issue text.