Remove trailing period on CEK-alg mismatch error to match the majority of error messages

Author: akareddy04

src/s3_encryption/materials/kms_keyring.py

@@ -205,7 +205,7 @@ def on_decrypt(self, dec_materials, encrypted_data_keys=None):
                     raise S3EncryptionClientError(
                         f"The content encryption algorithm in the KMS-authenticated encryption context "
                         f"'{kms_authenticated_algorithm}' does not match the algorithm suite selected "
-                        f"for decryption '{decryption_cek_algorithm}'."
+                        f"for decryption '{decryption_cek_algorithm}'"
                     )
 
             ##= specification/s3-encryption/materials/s3-kms-keyring.md#decryptdatakey