[nrf noup] ci: remove CI-zigbee-test

`CI-zigbee-test` not to be triggered anymore.

nrf-squash! [nrf noup] ci: add .github/test-spec.yml

Signed-off-by: Eduardo Montoya <eduardo.montoya@nordicsemi.no>

Author: edmont

.github/test-spec.yml

@@ -94,12 +94,6 @@
   - "tests/bluetooth/mesh/**/*"
   - "tests/bluetooth/mesh_shell/**/*"
 
-"CI-zigbee-test":
-  - "subsys/mgmt/mcumgr/**/*"
-  - "subsys/dfu/**/*"
-  - "include/mgmt/mcumgr/**/*"
-  - "include/dfu/**/*"
-
 "CI-thingy91-test":
   - "boards/nordic/nrf9160dk/**/*"
   - "arch/x86/core/**/*"