Fix Get and Preview calls for local extensions (#14841)

The PR corrects the issue where `Get` and `Preview` operations were
incorrectly calling `Delete` and `CreateOrUpdate`.
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src/Bicep.Local.Deploy/Extensibility/LocalExtensibilityHostManager.cs

@@ -80,14 +80,14 @@ private async Task<HttpResponseMessage> CallExtension(
             case "get":
                 {
                     var resourceReference = await GetResourceReferenceAsync(await content.ReadAsStreamAsync(cancellationToken), cancellationToken);
-                    var extensionResponse = await provider.Delete(resourceReference, cancellationToken);
+                    var extensionResponse = await provider.Get(resourceReference, cancellationToken);
 
                     return await GetHttpResponseMessageAsync(extensionResponse, cancellationToken);
                 }
             case "preview":
                 {
                     var resourceSpecification = await GetResourceSpecificationAsync(await content.ReadAsStreamAsync(cancellationToken), cancellationToken);
-                    var extensionResponse = await provider.CreateOrUpdate(resourceSpecification, cancellationToken);
+                    var extensionResponse = await provider.Preview(resourceSpecification, cancellationToken);
 
                     return await GetHttpResponseMessageAsync(extensionResponse, cancellationToken);
                 }