Previously, Site Editor client-side routing started using only the path query argument for loading non-editor views. The router removed the `postType` query
argument, which caused an error message to be displayed when the template parts list page was reloaded.
This changeset fixes the issue as it was affecting hybrid themes.
Props Mamaduka, isabel_brison, ramonopoly.
Fixes#58889.
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git-svn-id: http://core.svn.wordpress.org/trunk@55814 1a063a9b-81f0-0310-95a4-ce76da25c4cd