Display all pages in Solr search results by default

Use case:

1. Go to Administration: Localization
2. Set the Default Language to English
3. Create a new page (P1)
4. Go to Administration: Localization
5. Set the Default Language to French
6. Search for P1

P1 does not appear in the search results unless you tick English inside the Language facet.

By default Solr ticks the "No Language" and the current language for the Language facet.
I don't think this behaviour is user friendly.
Filters are supposed to help users find what they are searching for easier, but a certain filter shouldn't be enforced.

This issue can be fixed by deleting this line: https://github.com/xwiki/xwiki-platform/blob/stable-8.4.x/xwiki-platform-core/xwiki-platform-search/xwiki-platform-search-solr/xwiki-platform-search-solr-ui/src/main/resources/Main/SolrSearchConfig.xml#L74