fix(config-resolver): resolve region first from regionHash

Author: trivikr

packages/config-resolver/src/regionInfo/getRegionInfo.spec.ts

@@ -52,7 +52,7 @@ describe(getRegionInfo.name, () => {
   });
 
   const getMockResolvedRegion = (regionCase: RegionCase): string =>
-    regionCase === RegionCase.REGION ? mockRegion : mockEndpointRegion;
+    regionCase !== RegionCase.ENDPOINT ? mockRegion : mockEndpointRegion;
 
   const getMockResolvedPartitionOptions = (partitionHash) => ({ partitionHash });
 

packages/config-resolver/src/regionInfo/getRegionInfo.ts

@@ -17,7 +17,7 @@ export const getRegionInfo = (
   { signingService, regionHash, partitionHash }: GetRegionInfoOptions
 ): RegionInfo => {
   const partition = getResolvedPartition(region, { partitionHash });
-  const resolvedRegion = partitionHash[partition]?.endpoint ?? region;
+  const resolvedRegion = region in regionHash ? region : partitionHash[partition]?.endpoint ?? region;
 
   const hostname = getResolvedHostname(resolvedRegion, {
     signingService,