test: misc|shell: disable "zephyr,entropy" chosen property

When "zephyr,entropy" is enabled the corresponding entropy driver is
pulled in the build and initialized during boot. This

- changes the initialization sequence expected by "check_init_priorities";
- add one extra device to the expected list in "shell_device_filter".

Therefore this commit removes the "zephyr,entropy" propery to return the
test to the original state.

Signed-off-by: Valerio Setti <vsetti@baylibre.com>