Tc cnet 4 9 (project-chip#37884)

* TC-CNET-4.9 structure

* Implement step 1 and 2

* Typo and cluster update

* Implement more test steps

* Adding assertions

* Completed test steps

* Fixes. Removed from CI, test updated

* Remove unused imports

* Restyle

* Restyle

* Restyle

* Remove from manual tests list

* Adding more test steps. Now it adds a network after deleting it and checks if it's ok

* Restyle

* Restyle

* Restyle

* Restyle

* Removing CI block

* Reading networks from all endpoints. Adding logs

* Restyle

* Adding verification that the connected network is the only one across all endpoints

* Reading Network attribute using read_single_attribute_all_endpoints() function and checking if there is only one network connected across all endpoints

* Typo

* Add docstring

* Test updated as test plan suggests

* Updating test steps

* Adding docstring

* Adding final step

Author: r-recchia

src/app/tests/suites/certification/Test_TC_CNET_4_9.yaml

@@ -91,7 +91,6 @@
         "Test_TC_CNET_4_3",
         "Test_TC_CNET_4_5",
         "Test_TC_CNET_4_6",
-        "Test_TC_CNET_4_9",
         "Test_TC_CNET_4_10",
         "Test_TC_CNET_4_11",
         "Test_TC_CNET_4_12",