Ensure different key ids use different client instances (#2374)

* Ensure different key ids use different client instances

* Minor cleanup

* Minor cleanup

Author: rayokota

src/Confluent.SchemaRegistry.Encryption.Aws/AwsKmsClient.cs

@@ -12,7 +12,7 @@ public class AwsKmsClient : IKmsClient
     {
         private AmazonKeyManagementServiceClient kmsClient;
         private string keyId;
-        
+
         public string KekId { get; }
 
         public AwsKmsClient(string kekId, AWSCredentials credentials)
@@ -36,7 +36,7 @@ public AwsKmsClient(string kekId, AWSCredentials credentials)
 
         public bool DoesSupport(string uri)
         {
-            return uri.StartsWith(AwsKmsDriver.Prefix); 
+            return KekId == uri;
         }
 
         public async Task<byte[]> Encrypt(byte[] plaintext)

src/Confluent.SchemaRegistry.Encryption.Azure/AzureKmsClient.cs

@@ -25,7 +25,7 @@ public AzureKmsClient(string kekId, TokenCredential tokenCredential)
 
         public bool DoesSupport(string uri)
         {
-            return uri.StartsWith(AzureKmsDriver.Prefix); 
+            return KekId == uri;
         }
 
         public async Task<byte[]> Encrypt(byte[] plaintext)

src/Confluent.SchemaRegistry.Encryption.Gcp/GcpKmsClient.cs

@@ -36,7 +36,7 @@ public GcpKmsClient(string kekId, GoogleCredential credential)
 
         public bool DoesSupport(string uri)
         {
-            return uri.StartsWith(GcpKmsDriver.Prefix);
+            return KekId == uri;
         }
 
         public async Task<byte[]> Encrypt(byte[] plaintext)

src/Confluent.SchemaRegistry.Encryption.HcVault/HcVaultKmsClient.cs

@@ -48,7 +48,7 @@ public HcVaultKmsClient(string kekId, string ns, string tokenId)
 
         public bool DoesSupport(string uri)
         {
-            return uri.StartsWith(HcVaultKmsDriver.Prefix);
+            return KekId == uri;
         }
 
         public async Task<byte[]> Encrypt(byte[] plaintext)