editor: Hide signature popover on editor scroll (#29149)

Closes #27845

This is also how VSCode tackles this issue. I think this should be
applicable to even more popovers across the editor and context menu, but
it can be addressed later.

Release Notes:

- Fixed the signature popover not hiding on editor scroll.

crates/editor/src/editor.rs

@@ -1723,6 +1723,7 @@ impl Editor {
                                 new_anchor.offset,
                             );
                         });
+                        editor.hide_signature_help(cx, SignatureHelpHiddenBy::Escape);
                     }
                 }
                 EditorEvent::Edited { .. } => {