Fix get_monit_services_status logic (sonic-net#16013)

What is the motivation for this PR?
The current logic simply checks for the keyword "status" in service_info without considering the context. If the keyword appears in 'last output' or another unintended section of the data, the logic misinterprets it.

How did you do it?
Ensuring "status" detection is specific to the intended line. Using a stricter parsing approach to avoid unintended matches.

How did you verify/test it?
Ran the test_pretest.py on kvm-t0 testbed. Captured the get_monit_services_status() output

tests/common/devices/sonic.py

@@ -532,11 +532,11 @@ def get_monit_services_status(self):
             return monit_services_status
 
         for index, service_info in enumerate(services_status_result["stdout_lines"]):
-            if "status" in service_info and "monitoring status" not in service_info:
+            if service_info.strip().startswith("status"):
                 service_type_name = services_status_result["stdout_lines"][index - 1]
                 service_type = service_type_name.split("'")[0].strip()
                 service_name = service_type_name.split("'")[1].strip()
-                service_status = service_info[service_info.find("status") + len("status"):].strip()
+                service_status = service_info.split("status", 1)[1].strip()
 
                 monit_services_status[service_name] = {}
                 monit_services_status[service_name]["service_status"] = service_status