Work around Konsole not recognizing file:://$hostname/path as local

(This regressed in version 4 which sends OSC 7 to all terminals)

Konsole has a bug: it does not recognize file:://$hostname/path as directory.
When we send that via OSC 7, that breaks Konsole's "Open Folder With"
context menu entry.

OSC 7 producers are strongly encouraged to set a non-empty hostname, but
it's not clear if consumers are supposed to accept an empty hostname (see
https://gitlab.freedesktop.org/terminal-wg/specifications/-/issues/20).
I think it should be fine; implementations should treat it as local path.

Let's work around the Konsole bug by omitting the hostname for now. This
may not be fully correct when using a remote desktop tool to access a
system running Konsole but I guess that's unlikely and understandable.
We're using KONSOLE_VERSION, so it the workaround should not leak into SSH
sessions where a hostname component is important.

Closes #11198

Proposed upstream fix https://invent.kde.org/frameworks/kio/-/merge_requests/1820

(cherry picked from commit c926a87bdb)

share/functions/__fish_config_interactive.fish

@@ -221,7 +221,11 @@ end" >$__fish_config_dir/config.fish
 
     # Notify terminals when $PWD changes via OSC 7 (issue #906).
     function __fish_update_cwd_osc --on-variable PWD --description 'Notify terminals when $PWD changes'
-        printf \e\]7\;file://%s%s\a $hostname (string escape --style=url -- $PWD)
+        set -l host $hostname
+        if set -q KONSOLE_VERSION
+            set host ''
+        end
+        printf \e\]7\;file://%s%s\a $host (string escape --style=url -- $PWD)
     end
     __fish_update_cwd_osc # Run once because we might have already inherited a PWD from an old tab