[thci] add setCcmState method in thci (#7179)

This commit adds API method setCcmState to THCI file.
diff --git a/tools/harness-thci/OpenThread.py b/tools/harness-thci/OpenThread.py
index 9dd9b4b..9f173a5 100644
--- a/tools/harness-thci/OpenThread.py
+++ b/tools/harness-thci/OpenThread.py
@@ -3604,6 +3604,11 @@
 
         return s
 
+    @API
+    def setCcmState(self, state=0):
+        assert state in (0, 1), state
+        self.__executeCommand("ccm {}".format("enable" if state == 1 else "disable"))
+
 
 class OpenThread(OpenThreadTHCI, IThci):