Fix regression causing cursor shape commands to leak into noninteractive shell

As reported in
https://matrix.to/#/!YLTeaulxSDauOOxBoR:matrix.org/$CLuoHTdvcRj_8-HBBq0p-lmGWeix5khEtKEDxN2Ulfo

Running

	fish -C '
		fzf_key_bindings
		echo fish_vi_key_bindings >>~/.config/fish/config.fish
		fzf-history-widget
	'

and pressing "enter" will add escape sequences like "[2 q" (cursor shape)
to fish's command line.

This is because fzf-history-widget binds "enter" to a filter
that happens to be a fish script:

	set -lx FZF_DEFAULT_OPTS \
		... \
		"--bind='enter:become:string replace -a -- \n\t \n {2..} | string collect'" \
		'--with-shell='(status fish-path)\\ -c)

The above ~/.config/fish/config.fish (redundantly) runs "fish_vi_key_bindings"
even in *noninteractive* shells, then "fish_vi_cursor" will print cursor
sequences in its "fish_exit" handler.  The sequence is not printed to the
terminal but to fzf which doesn't parse CSI commands.

This is a regression introduced by a5dfa84f73 (fish_vi_cursor: skip if stdin
is not a tty, 2023-11-14). That commit wanted "fish -c read" to be able to
use Vi cursor.  This is a noninteractive shell, but inside "read" we are
"effectively interactive".  However "status is-interactive" does not tell
us that.

Let's use a more contained fix to make sure that we print escape sequences only
if either fish is interactive, or if we are evaluating an interactive read.

In general, "fish -c read" is prone to configuration errors, since we
recommend gating configuration (for bind etc) on "status is-interactive"
which will not run here.

share/functions/fish_vi_cursor.fish

@@ -1,13 +1,11 @@
 function fish_vi_cursor -d 'Set cursor shape for different vi modes'
-    # if stdin is not a tty, there is effectively no bind mode.
-    if not test -t 0
-        return
-    end
-
     set -q fish_cursor_unknown
     or set -g fish_cursor_unknown block
 
     function __fish_vi_cursor --argument-names varname
+        if not status is-interactive; and not status is-interactive-read
+            return
+        end
         if not set -q $varname
             switch $varname
                 case fish_cursor_insert