refactor: rename kms feature flag to aws_kms (#3249)

Co-authored-by: hyperswitch-bot[bot] <148525504+hyperswitch-bot[bot]@users.noreply.github.com>

crates/external_services/src/aws_kms/decrypt.rs

@@ -0,0 +1,42 @@
+use common_utils::errors::CustomResult;
+
+use super::*;
+
+#[async_trait::async_trait]
+/// This trait performs in place decryption of the structure on which this is implemented
+pub trait AwsKmsDecrypt {
+    /// The output type of the decryption
+    type Output;
+    /// Decrypts the structure given a AWS KMS client
+    async fn decrypt_inner(
+        self,
+        aws_kms_client: &AwsKmsClient,
+    ) -> CustomResult<Self::Output, AwsKmsError>
+    where
+        Self: Sized;
+
+    /// Tries to use the Singleton client to decrypt the structure
+    async fn try_decrypt_inner(self) -> CustomResult<Self::Output, AwsKmsError>
+    where
+        Self: Sized,
+    {
+        let client = AWS_KMS_CLIENT
+            .get()
+            .ok_or(AwsKmsError::AwsKmsClientNotInitialized)?;
+        self.decrypt_inner(client).await
+    }
+}
+
+#[async_trait::async_trait]
+impl AwsKmsDecrypt for &AwsKmsValue {
+    type Output = String;
+    async fn decrypt_inner(
+        self,
+        aws_kms_client: &AwsKmsClient,
+    ) -> CustomResult<Self::Output, AwsKmsError> {
+        aws_kms_client
+            .decrypt(self.0.peek())
+            .await
+            .attach_printable("Failed to decrypt AWS KMS value")
+    }
+}