fix(eks): helm private ecr in govcloud (#26794)

Using helm charts in a private ECR repo is not possible in govcloud regions, as the regex is too narrowly defined.

This change will properly match against all current AWS regions.

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*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/aws-cdk-lib/aws-eks/lib/kubectl-handler/helm/__init__.py

@@ -100,7 +100,7 @@ def helm_handler(event, context):
 
 def get_oci_cmd(repository, version):
     # Generates OCI command based on pattern. Public ECR vs Private ECR are treated differently.
-    private_ecr_pattern = 'oci://(?P<registry>\d+.dkr.ecr.(?P<region>[a-z]+-[a-z]+-\d).amazonaws.com)*'
+    private_ecr_pattern = 'oci://(?P<registry>\d+.dkr.ecr.(?P<region>[a-z0-9\-]+).amazonaws.com)*'
     public_ecr_pattern = 'oci://(?P<registry>public.ecr.aws)*'
 
     private_registry = re.match(private_ecr_pattern, repository).groupdict()