project panel: Fix alignment of entries overflowing the panel. (#10676)

With file icons turned off, we still reserve space for an icon and make
it invisible. However, that space was marked as flex, which made it
shrink in case subsequent file name could not fit in the current width
of the project panel. Fixes #10622



https://github.com/zed-industries/zed/assets/24362066/d565a03a-3712-49d1-bf52-407e4508a8cf


Release Notes:


- Fixed project panel entries misalignment with narrow panel & file
icons turned off.

crates/project_panel/src/project_panel.rs

@@ -1642,7 +1642,10 @@ impl ProjectPanel {
                     .child(if let Some(icon) = &icon {
                         h_flex().child(Icon::from_path(icon.to_string()).color(filename_text_color))
                     } else {
-                        h_flex().size(IconSize::default().rems()).invisible()
+                        h_flex()
+                            .size(IconSize::default().rems())
+                            .invisible()
+                            .flex_none()
                     })
                     .child(
                         if let (Some(editor), true) = (Some(&self.filename_editor), show_editor) {