fix: supporting diskstatus(outage info) for all cases in disk dashboard

[Hardikl]

Result of the query: label_join(disk_labels{datacenter="DC-03",cluster="F8080-32-25"}, "diskStatus", " ","NonSupportedField", "outage")

1. When no outage info available in disk_labels:

disk_labels{aggr="aggr0_F8080_32_25_01", cluster="F8080-32-25", datacenter="DC-03", disk="1.0.12", diskStatus=" ", failed="false", instance="localhost:12991", job="prometheus1", model="X446_1625200MCSG", node="F8080-32-25-01", owner_node="F8080-32-25-01", serial_number="S142NEAG200663", shared="true", shelf="0", shelf_bay="12", type="SSD"}	1

2. When outage info available in disk_labels:

disk_labels{cluster="F8080-32-25", datacenter="DC-03", disk="1.10.4", diskStatus=" unknown", failed="false", instance="localhost:12991", job="prometheus1", model="X446_1625200MCSG", node="F8080-32-22-01", outage="unknown", owner_node="F8080-32-22-01", serial_number="S142NEAG102094", shared="true", shelf="10", shelf_bay="4", type="SSD"}	1

DC-03:

DC-02:

[cgrinds]

thanks @Hardikl