If {nav System Settings > Applications > Default Applications > Web Browser} is using the setting "In an application based on the contents of the URL", then lookup can fail and pass the URL to the wrong app when no default app is set in `kdeglobals` and `mimeapps.list` has no `x-scheme-handler/https` or `x-scheme-handler/http` entries, but does have an entry for `text/html`.
This patch makes KRun additionally fall back to reading from `text/html` in `mimeapps.list` if it's present.