indexer-agent: Fix bug in stake usage summary

- If null POI is provided we should expect that the agent will get a
valid POI from the graph-node. I.e only expect 0 rewards if a 0x0...
POI is explicitly provided

packages/indexer-common/src/indexer-management/allocations.ts

@@ -999,10 +999,10 @@ export class AllocationManager {
       // Fetch the allocation on chain to inspect its amount
       const allocation = await this.network.networkMonitor.allocation(action.allocationID)
 
-      // Accrue rewards, except for null or zeroed POI
+      // Accrue rewards, except for zeroed POI
       const zeroHexString = utils.hexlify(Array(32).fill(0))
       rewards =
-        !action.poi || action.poi === zeroHexString
+        action.poi === zeroHexString
           ? BigNumber.from(0)
           : await this.network.contracts.rewardsManager.getRewards(action.allocationID)