Update CODEOWNERS for Health Deidentification (#32180)

### Packages impacted by this PR


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### Describe the problem that is addressed by this PR


### What are the possible designs available to address the problem? If
there are more than one possible design, why was the one in this PR
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### Are there test cases added in this PR? _(If not, why?)_


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### Command used to generate this PR:**_(Applicable only to SDK release
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### Checklists
- [x] Added impacted package name to the issue description
- [x] Does this PR needs any fixes in the SDK Generator?** _(If so,
create an Issue in the
[Autorest/typescript](https://github.com/Azure/autorest.typescript)
repository and link it here)_
- [x] Added a changelog (if necessary)

.github/CODEOWNERS

@@ -147,7 +147,7 @@
 
 # ServiceLabel: %Health Deidentification
 # PRLabel: %Health Deidentification
-/sdk/healthdataaiservices/azure-health-deidentification/ @GrahamMThomas
+/sdk/healthdataaiservices/azure-health-deidentification/ @GrahamMThomas @alexathomases
 
 # PRLabel: %Azure.Identity
 /sdk/identity/ @KarishmaGhiya @minhanh-phan @maorleger @schaabs @Azure/azure-sdk-write-identity