chore(): Use the config region in key-manager (#870)

* chore(): Use the config region in key-manager

* fmt

iris-mpc-common/src/helpers/key_pair.rs

@@ -83,7 +83,12 @@ impl Drop for SharesEncryptionKeyPairs {
 
 impl SharesEncryptionKeyPairs {
     pub async fn from_storage(config: Config) -> Result<Self, SharesDecodingError> {
-        let region_provider = Region::new(REGION);
+        // use the configured region, fallback to the hardcoded value
+        let region = config
+            .aws
+            .and_then(|aws| aws.region)
+            .unwrap_or_else(|| REGION.to_owned());
+        let region_provider = Region::new(region);
         let shared_config = aws_config::from_env().region(region_provider).load().await;
         let client = SecretsManagerClient::new(&shared_config);