Azure: remove 1.25 periodic jobs (#31246)

* Azure: remove 1.25 periodic jobs

* remove dashboard tabs

Author: CecileRobertMichon

config/jobs/kubernetes/sig-cloud-provider/azure/README.md

@@ -5,5 +5,5 @@ Job configurations for https://testgrid.k8s.io/provider-azure.
 To generate the job configurations for 1.23, 1.24, 1.25, 1.26, and master branch:
 
 ```bash
-./generate.sh 1.25 1.26 1.27 1.28 master
+./generate.sh 1.26 1.27 1.28 master
 ```