fix: /extended/v2/pox/cycles/{n}/signers/{key}/stackers returning 500 error

Author: zone117x

src/datastore/pg-store-v2.ts

@@ -908,7 +908,7 @@ export class PgStoreV2 extends BasePgStoreModule {
             cs.stacker_type,
             COUNT(*) OVER()::int AS total
         FROM pox_sets ps
-        LEFT JOIN combined_stackers cs ON ps.signing_key = cs.signer_key
+        INNER JOIN combined_stackers cs ON ps.signing_key = cs.signer_key
         WHERE ps.canonical = TRUE 
           AND ps.cycle_number = ${cycleNumber} 
           AND ps.signing_key = ${signerKey}