[Guardrails] Increase of Replica count shouldn't be allowed after the Disk usage per node Guardrail has been breached

Steps:

1. Initialise a 3 node cluster running just the KV service.
2. Create a Magma bucket named 'default' with 512MB RAM per node and 1 replica.
3. Load 11 million documents into the bucket. After initial loading, the disk usage on the three nodes was [1.0, 1.0, 1.0]
4. Now configure maximum=0.5 for diskUsage guardrail in http://172.23.106.202:8091/settings/resourceManagement
   This is done to breach the disk usage per node guardrail.
5. Created a new bucket, validated that mutations were blocked for both the buckets by inserting a few documents and got the error 'BUCKET_DISK_SPACE_TOO_LOW'.
6. Updated the replicaNumber to 2 for bucket 'default' and rebalanced the cluster.
7. Disk usage of the three nodes after replica update was [1.0, 1.0, 2.0]
8. Since increasing of replicas would add more data to the disk and would cause an increase in the disk usage, the operation shouldn't be allowed.