workspace: Prefer active window over other local non-collab windows for opening file (#23726)

Closes #21625 #17401 #16426

This is how the opening of a file works currently:

1. We first check if the file is part of any existing worktree. If it
is, we focus on that file in the worktree, and the window is activated.
2. If the file is not part of any worktree, we open it in the first
local non-collab workspace we find and activate that window. This is the
bug that the issues are based on.

This PR fixes it by modifying the second part of the above step, where
the file is not part of any worktree. Now, we will first open the file
in the active window, but only if the active window is local and
non-collab. This resolves the issue. If the file can't be opened in the
active window due to the local non-collab check, we will carry out the
existing logic of opening the file in whichever window is local and
non-collab.

I have tested this using the "workspace::OpenFiles" action, and
"workspace::Open" also uses the same method. That is, it will work on
all platforms.

Future: Some users also mentioned there should be a setting for whether
we should open a non-workspace file in the existing window or in a
separate new window. However, this seems out of scope, and a new issue
should be created for this.

#9370 is related, but this likely doesn't fix it, as it deals with how
macOS Finder's "Open with" handles files. I don't have macOS to test,
but this PR won't resolve it if Finder always opens a new window.

Release Notes:

- Fixed the issue where a file outside of the workspace was opening in a
random window instead of the last active window.

crates/workspace/src/workspace.rs

@@ -5944,6 +5944,19 @@ pub fn open_paths(
                 .all(|file| !file.is_dir)
             {
                 cx.update(|cx| {
+                    if let Some(window) = cx
+                        .active_window()
+                        .and_then(|window| window.downcast::<Workspace>())
+                    {
+                        if let Ok(workspace) = window.read(cx) {
+                            let project = workspace.project().read(cx);
+                            if project.is_local() && !project.is_via_collab() {
+                                existing = Some(window);
+                                open_visible = OpenVisible::None;
+                                return;
+                            }
+                        }
+                    }
                     for window in local_workspace_windows(cx) {
                         if let Ok(workspace) = window.read(cx) {
                             let project = workspace.project().read(cx);