Suppress CustomerManagedKeyEncryption deprecation in devcenter spec

Add #suppress "deprecated" directives to devcenter TypeSpec files
that reference CustomerManagedKeyEncryption, which is being deprecated
in favor of the Encryption type in typespec-azure.

The devcenter spec uses v4 common-types and these references remain
valid for backward compatibility.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: markcowl

specification/devcenter/DevCenter.Management/client.tsp

@@ -223,6 +223,7 @@ using Microsoft.DevCenter;
 );
 @@clientName(CatalogSyncError, "DevCenterCatalogSyncError", "csharp");
 @@clientName(ConfigurationPolicies, "DevCenterConfigurationPolicies", "csharp");
+#suppress "deprecated" "Continuing to use v4 CustomerManagedKeyEncryption for backward compatibility"
 @@clientName(
   Azure.ResourceManager.CommonTypes.CustomerManagedKeyEncryption,
   "DevCenterCustomerManagedKeyEncryption",

specification/devcenter/DevCenter.Management/models.tsp

@@ -685,6 +685,7 @@ model DevCenterUpdateProperties {
 @doc("Encryption properties.")
 model Encryption {
   @doc("All Customer-managed key encryption properties for the resource.")
+  #suppress "deprecated" "Continuing to use v4 CustomerManagedKeyEncryption for backward compatibility"
   customerManagedKeyEncryption?: CustomerManagedKeyEncryption;
 }