Improve gnmi setup (#7646)

What is the motivation for this PR?
If gnmi program is running, no need to restart.

How did you do it?
Check program status, return for running state.

How did you verify/test it?
Run GNMI end2end test

tests/gnmi/helper.py

@@ -42,6 +42,10 @@ def apply_cert_config(duthost):
 
 
 def recover_cert_config(duthost):
+    dut_command = "docker exec %s supervisorctl status %s" % (GNMI_CONTAINER_NAME, GNMI_PROGRAM_NAME)
+    output = duthost.command(dut_command, module_ignore_errors=True)['stdout'].strip()
+    if 'RUNNING' in output:
+        return
     dut_command = "docker exec %s pkill telemetry" % (GNMI_CONTAINER_NAME)
     duthost.shell(dut_command, module_ignore_errors=True)
     dut_command = "docker exec %s supervisorctl start %s" % (GNMI_CONTAINER_NAME, GNMI_PROGRAM_NAME)