project_panel: Open file in editor on paste action when single entry (#25555)

Closes #25145

Now, upon pasting a file into the project panel after a copy or cut
operation, it will open in the editor. This buffer in the editor will be
in focus if there is no need to rename the newly pasted file. If a
rename is pending, it simply focuses on the rename editor.


https://github.com/user-attachments/assets/563b22ec-d1f6-4d92-af18-29d10620832c


Future: After the rename is completed, we can decide to focus on the
editor buffer, but this will be addressed in a follow-up, as there will
be multiple cases, such as renaming via a paste action where we want to
focus, and renaming directly via a rename action where we might not want
to focus.

Release Notes:

- Fixed scenario where pasting a file in the project panel after a
copy/cut operation wouldn't automatically open it in the editor.