Show file open error view instead of the modal (#36764)

Closes https://github.com/zed-industries/zed/issues/36672

Before:
either 
<img width="966" height="642" alt="image"
src="https://github.com/user-attachments/assets/7263ea3c-3d48-4f4d-be9e-16b24ca6f60b"
/>
(when opening from the project panel)

or

<img width="959" height="1019" alt="image"
src="https://github.com/user-attachments/assets/834041d4-f4d6-46db-b333-803169ec4803"
/>

(for the rest of the cases)

After:

<img width="2032" height="1167" alt="Screenshot 2025-08-22 at 19 34 10"
src="https://github.com/user-attachments/assets/1aa4530b-69f6-4c3a-8ea1-d4035dbb28da"
/>

(the unified error view)

Release Notes:

- Improved unsupported file opening in Zed

---------

Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>

crates/project_panel/src/project_panel.rs

@@ -69,6 +69,7 @@ use workspace::{
     notifications::{DetachAndPromptErr, NotifyTaskExt},
 };
 use worktree::CreatedEntry;
+use zed_actions::workspace::OpenWithSystem;
 
 const PROJECT_PANEL_KEY: &str = "ProjectPanel";
 const NEW_ENTRY_ID: ProjectEntryId = ProjectEntryId::MAX;
@@ -255,8 +256,6 @@ actions!(
         RevealInFileManager,
         /// Removes the selected folder from the project.
         RemoveFromProject,
-        /// Opens the selected file with the system's default application.
-        OpenWithSystem,
         /// Cuts the selected file or directory.
         Cut,
         /// Pastes the previously cut or copied item.