fix(aws): resolve endpoint if endpoint is passed (#4925)

* fix(aws): resolve endpoint to get identity if endpoint is passed

* resolve endpoint for ami and ebs

* return an error if aws region is missing

integration/aws_cloud_test.go

@@ -32,7 +32,7 @@ func TestAwsCommandRun(t *testing.T) {
 				"AWS_ACCESS_KEY_ID":     "test",
 				"AWS_SECRET_ACCESS_KEY": "test",
 			},
-			wantErr: "Invalid Configuration: Missing Region",
+			wantErr: "aws region is required",
 		},
 		{
 			name: "fail without creds",