Remove the warning message appear when there are no ports on CONFIG DB (#2050)

#### What I did

Remove the warning of "Configuration database contains no ports" when ports table is empty.
Because when having a system with zero ports, this message appear per each access to ports tables on CONFIG DB

For example:

Run any cli command. For example  "show boot" or "show int st"

Observed behavior

root@r-sn4800-simx:/home/admin# show boot
Configuration database contains no ports
Configuration database contains no ports
Configuration database contains no ports


#### How I did it

Remove the warning and remove the unit test verify this warning 

#### How to verify it

Remove all the ports and verify there is no such warning in case of running "show interface status" CLi command

#### Previous command output (if the output of a command-line utility has changed)

Configuration database contains no ports
  Interface    Lanes    Speed    MTU    FEC    Alias    Vlan    Oper    Admin    Type    Asym PFC
-----------  -------  -------  -----  -----  -------  ------  ------  -------  ------  ----------
 
#### New command output (if the output of a command-line utility has changed)

  Interface    Lanes    Speed    MTU    FEC    Alias    Vlan    Oper    Admin    Type    Asym PFC
-----------  -------  -------  -----  -----  -------  ------  ------  -------  ------  ----------

Author: dprital

tests/interfaces_test.py

@@ -293,7 +293,7 @@ def test_show_interfaces_portchannel_in_alias_mode(self):
         traceback.print_tb(result.exc_info[2])
         assert result.exit_code == 0
         assert result.output == show_interfaces_portchannel_in_alias_mode_output
-        
+       
     @mock.patch('sonic_py_common.multi_asic.get_port_table', mock.MagicMock(return_value={}))
     def test_supervisor_show_interfaces_alias_etp1_with_waring(self):
         runner = CliRunner()
@@ -303,8 +303,7 @@ def test_supervisor_show_interfaces_alias_etp1_with_waring(self):
         print(result.exit_code)
         print(result.output)
         assert result.exit_code != 0
-        assert "Configuration database contains no ports" in result.output
-        
+
     @mock.patch('sonic_py_common.multi_asic.get_port_table', mock.MagicMock(return_value={}))
     @mock.patch('sonic_py_common.device_info.is_supervisor', mock.MagicMock(return_value=True))
     def test_supervisor_show_interfaces_alias_etp1_without_waring(self):
@@ -315,8 +314,7 @@ def test_supervisor_show_interfaces_alias_etp1_without_waring(self):
         print(result.exit_code)
         print(result.output)
         assert result.exit_code != 0
-        assert "Configuration database contains no ports" not in result.output
-        
+
     @classmethod
     def teardown_class(cls):
         print("TEARDOWN")

utilities_common/cli.py

@@ -10,7 +10,7 @@
 import netaddr
 
 from natsort import natsorted
-from sonic_py_common import multi_asic, device_info
+from sonic_py_common import multi_asic
 from utilities_common.db import Db
 from utilities_common.general import load_db_config
 
@@ -131,8 +131,6 @@ def __init__(self, db=None):
 
 
         if not self.port_dict:
-            if not device_info.is_supervisor():
-                click.echo(message="Configuration database contains no ports")
             self.port_dict = {}
 
         for port_name in self.port_dict: