Add a delay for 'test_ro_user' case 'test_ro_user_banned_command' to allow 'hostcfgd' to start and configure tacas authorization. (sonic-net#3741)

- What is the motivation for this PR?
After recent change introduced on this PR's: sonic-net/sonic-buildimage#7965 and sonic-net/sonic-buildimage#8117 'hostcfgd' will be delayed in 90 seconds.
If the test will run before the daemon has started, it will fail the test. This is to align with the new change and make sure the test will pass.

- How did you do it?
Add a delay of 100 seconds before executing authorized commands.

- How did you verify/test it?
Run the test.

Signed-off-by: Shlomi Bitton <shlomibi@nvidia.com>

Author: shlomibitton

tests/tacacs/test_ro_user.py

@@ -1,4 +1,5 @@
 import pytest
+import time
 from tests.common.helpers.assertions import pytest_assert
 
 pytestmark = [
@@ -151,6 +152,8 @@ def test_ro_user_banned_command(localhost, duthosts, enum_rand_one_per_hwsku_hos
             'sudo config'
     ]
 
+    # Wait until hostcfgd started and configured tacas authorization
+    time.sleep(100)
     for command in commands:
         banned = ssh_remote_ban_run(localhost, dutip, creds_all_duts[duthost]['tacacs_ro_user'],
                                     creds_all_duts[duthost]['tacacs_ro_user_passwd'], command)