Tools: Fix shebang for MacOs

Revert a change introduced in d296aad2a9
for intended compatibility with BSD which breaks the build on MacOs:
"clang: error: unknown argument: '-n'" for "echo".

BSD users will have to use some workaround since MacOs is a supported
OS of IDF and BSD is not.

tools/kconfig/lxdialog/check-lxdialog.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 # Check ncurses compatibility
 
 # What library to link