[ML] Search bar does not apply initial pinned filters

[jgowdyelastic]

Affects Index Data Visualizer, Log Rate Analysis and Log Pattern Analysis.

When pinning filters to the search bar and navigating away and back again, the initial filters are not applied. Interacting with the search bar, either by adjusting the filters or simply focusing on the search bar and pressing enter, causes the filters to be applied. It appears there is no way to get the initial state from Kibana's SearchBar component for us to use when loading the page. Ideally the SearchBar component would allow us to pass in a callback function so we can retrieve its state at any time.

[elasticmachine]

Pinging @elastic/ml-ui (:ml)