fix: a credential or host-key prompt takes Enter and Escape from the modals underneath

Every modal read Enter/Escape globally, so a prompt that popped up over a
dialog, the palette, Quick Connect or an SFTP dialog could be answered
and the modal underneath confirmed or dismissed by the same key press.
All modals except the prompts now read those keys through
chrome::modal_key, which yields while a prompt is on screen.

rust/app/src/sftp.rs

@@ -772,8 +772,8 @@ impl Sftp {
             return;
         };
         let t = Tokens::get(ctx);
-        let esc = ctx.input(|i| i.key_pressed(Key::Escape));
-        let enter = ctx.input(|i| i.key_pressed(Key::Enter));
+        let esc = crate::chrome::modal_key(ctx, Key::Escape);
+        let enter = crate::chrome::modal_key(ctx, Key::Enter);
         let mut keep = !esc;
         match &mut d {
             Dialog::Input { session, kind, value } => {
@@ -961,7 +961,7 @@ impl Sftp {
                     }
                 }
             }
-            if ctx.input(|i| i.key_pressed(Key::Enter)) && writable && !target.is_empty() {
+            if crate::chrome::modal_key(ctx, Key::Enter) && writable && !target.is_empty() {
                 chosen = Some(target.clone());
             }
             if back && pk.filter.is_empty() && !pk.cwd.is_empty() && pk.cwd != "/" {