Revert "Latch signal handlers"

This reverts commit 7ed1022cf4.

Fixes #5962.

src/reader.cpp

@@ -1744,7 +1744,7 @@ static void reader_interactive_init() {
             }
         }
 
-        signal_set_handlers(shell_is_interactive());
+        signal_set_handlers();
     }
 
     // It shouldn't be necessary to place fish in its own process group and force control