[Discover] Pinned filters are ignored when fetching results for a saved search via a custom link

[jughosta]

Kibana version: at least in 8.11 and above

Description of the problem including expected versus actual behavior:
If a saved search includes filters and URL is manually constructed to include pinned filters then the pinned filters are ignored after opening the URL.

Steps to reproduce:

1. Create a saved search with some filters and save it
2. Create a new filter and pin it => Make note of the current Discover URL and copy it including _g=... and excluding _a=... param (example: http://localhost:5601/qzv/app/discover#/view/2f360f30-ea74-11eb-b4c6-3d2afc1cb389?_g=(filters:!(('$state':(store:globalState),meta:(alias:!n,disabled:!f,index:'90943e30-9a47-11e8-b64d-95841ca0b247',key:machine.os,negate:!f,params:(query:ios),type:phrase),query:(match_phrase:(machine.os:ios)))),refreshInterval:(pause:!t,value:60000),time:(from:now-30d%2Fd,to:now)))
3. Visit the URL

Expected: both filters (pinned and from the saved search) are applied
Actual: only the saved search filter was used to fetch results

[elasticmachine]

Pinging @elastic/kibana-data-discovery (Team:DataDiscovery)

[jughosta]

To check: https://github.com/elastic/kibana/blob/main/src/plugins/discover/public/application/main/services/load_saved_search.ts#L128-L132

[kertal]

To check: https://github.com/elastic/kibana/blob/main/src/plugins/discover/public/application/main/services/load_saved_search.ts#L128-L132

@jughosta Yes, that's for sure the right file, but I think it's likely because of this code:

kibana/src/plugins/discover/public/application/main/services/load_saved_search.ts

Lines 70 to 89 in f606085

	if (appState) {
	if (savedSearchId && appState.index) {
	// This is for the case appState is overwriting the loaded saved search data view
	const savedSearchDataViewId = nextSavedSearch.searchSource.getField('index')?.id;
	const stateDataView = await getStateDataView(params, {
	services,
	appState,
	internalStateContainer,
	savedSearch: nextSavedSearch,
	});
	const dataViewDifferentToAppState = stateDataView.id !== savedSearchDataViewId;
	if (stateDataView && (dataViewDifferentToAppState || !savedSearchDataViewId)) {
	nextSavedSearch.searchSource.setField('index', stateDataView);
	}
	}
	nextSavedSearch = savedSearchContainer.update({
	nextDataView: nextSavedSearch.searchSource.getField('index'),
	nextState: appState,
	});
	}

Since appState is empty initially (no _a in URL), the saved search is not updated (at L84), and that's why the global filter isn't being applied at the initial loading of the saved search, and the data fetching is done without the global state