Bug: UI filter buttons in expanded view of Explorer results remove previously chosen filters

[cseas]

Actual behaviour

When we add filters using the UI in Explorer page, they get added to the previously selected filters.

But when we select the filters from one of the attributes after expanding a search result, the filter removes all of the previously selected filters from the search bar.

Expected behaviour

Filters from the expanded view of results should also be added to the existing filters instead of replacing them entirely.

[cseas]

@anandtiwary @aaron-steinfeld @itssharmasandeep

[cseas]

The filter in the top level explorer results works correctly because it is a filter-button that uses the addUrlFilter method.

The filter button in the expanded view of a result is buggy because it is instead a link that navigates to a URL with the new filter applied, completing wiping out any previously added filters.

[cseas]

Same bug exists in the Services page:

And also the API Endpoints page:

#1766 fixes the bug at these places as well.