refactor: remove API key parameter and switch to AAD authentication for AI Foundry connection

Author: Abdul-Microsoft

infra/main.bicep

@@ -1759,7 +1759,6 @@ module aiSearchFoundryConnection 'modules/aifp-connections.bicep' = {
     searchServiceResourceId: searchService.id
     searchServiceLocation: searchService.location
     searchServiceName: searchService.name
-    searchApiKey: searchService.listAdminKeys().primaryKey
   }
   dependsOn: [
     aiFoundryAiServices

infra/modules/aifp-connections.bicep

@@ -1,21 +1,27 @@
+@description('Name of the AI Foundry search connection')
 param aifSearchConnectionName string
+
+@description('Name of the Azure AI Search service')
 param searchServiceName string
+
+@description('Resource ID of the Azure AI Search service')
 param searchServiceResourceId string
+
+@description('Location/region of the Azure AI Search service')
 param searchServiceLocation string
+
+@description('Name of the AI Foundry account')
 param aiFoundryName string
+
+@description('Name of the AI Foundry project')
 param aiFoundryProjectName string
-@secure()
-param searchApiKey string
 
 resource aiSearchFoundryConnection 'Microsoft.CognitiveServices/accounts/projects/connections@2025-04-01-preview' = {
   name: '${aiFoundryName}/${aiFoundryProjectName}/${aifSearchConnectionName}'
   properties: {
     category: 'CognitiveSearch'
     target: 'https://${searchServiceName}.search.windows.net'
-    authType: 'ApiKey'
-    credentials: {
-      key: searchApiKey
-    }
+    authType: 'AAD'
     isSharedToAll: true
     metadata: {
       ApiType: 'Azure'