Remove network acl (Azure-Samples#236)

## Purpose
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does it solve or functionality does it add? -->
* ...
Azure-Samples#219 
## Does this introduce a breaking change?
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[ ] Yes
[ ] No
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## Pull Request Type
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[ ] Bugfix
[ ] Feature
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[ ] Refactoring (no functional changes, no api changes)
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[ ] Other... Please describe:
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git clone [repo-address]
cd [repo-name]
git checkout [branch-name]
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infra/core/ai/cognitiveservices.bicep

@@ -18,9 +18,6 @@ resource account 'Microsoft.CognitiveServices/accounts@2023-05-01' = {
   properties: {
     customSubDomainName: customSubDomainName
     publicNetworkAccess: publicNetworkAccess
-    networkAcls: {
-      defaultAction: 'Allow'
-    }
   }
   sku: sku
 }