ci: TestUtils.py: Fix process matching in ssh_force_kill method

* Updated `pgrep` to use the `-f` option for matching the full command
  line instead of just the process name.
* Ensures more reliable process identification, especially for cases
  where only part of the command line matches the specified text.

.ci/robot_framework/libs/TestUtils.py

@@ -62,7 +62,7 @@ def ssh_command_in_background(self, ip, command):
     def ssh_force_kill(self, ip, text):
         """Force kill all related process."""
         print(f"RUN: Killing all '{text}' related processes ...")
-        command = f"pgrep {text} && pgrep {text} | xargs kill -9 || echo '{text} not running'"
+        command = f"pgrep -f {text} && pgrep -f {text} | xargs kill -9 || echo '{text} not running'"
         return self.ssh_command(ip, command, quiet=True)
 
     def ssh_reboot_force_reboot(self, ip):