Grok Pattern Filter in Edit Modal depends on Filter of Overview

## Expected Behavior
When you edit a Grok Pattern, you have a list of the available Grok Patterns on the side in the Edit Modal. You should be able to easily filter this list.

## Current Behavior
If you first filter on the overview page, this filter is also applied to the list in the edit modal. This means you only have a limited view of available Grok patterns

## Steps to Reproduce (for bugs)
1. Go to the Grok Pattern overview page
1. Filter by date in the overview.
1. Create a new Grok Pattern
1. With the modal now open, only the Grok patterns that contain “Date” can be seen.

## Your Environment
* Graylog Version: Graylog 6.0.0-SNAPSHOT+2d4b321
**Might be a problem in 5.2**