Try anonymous auth first when pull from container registry (#14984)

Currently, we attempt anonymous authentication only after authenticated
client authentication fails. However, it would be more logical to
reverse this approach, as pulling from MCR is typically the more common
use case.

Closes #14774.
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src/Bicep.Core/Registry/AzureContainerRegistryManager.cs

@@ -45,22 +45,21 @@ async Task<OciArtifactResult> DownloadManifestInternalAsync(bool anonymousAccess
 
             try
             {
-                // Try authenticated client first.
-                Trace.WriteLine($"Authenticated attempt to pull artifact for module {artifactReference.FullyQualifiedReference}.");
-                return await DownloadManifestInternalAsync(anonymousAccess: false);
+                // Try anonymous auth first.
+                Trace.WriteLine($"Attempt to pull artifact for module {artifactReference.FullyQualifiedReference} with anonymous authentication.");
+                return await DownloadManifestInternalAsync(anonymousAccess: true);
             }
-            catch (RequestFailedException exception) when (exception.Status == 401 || exception.Status == 403)
+            catch (RequestFailedException requestedFailedException) when (requestedFailedException.Status is 401 or 403)
             {
-                // Fall back to anonymous client.
-                Trace.WriteLine($"Authenticated attempt to pull artifact for module {artifactReference.FullyQualifiedReference} failed, received code {exception.Status}. Fallback to anonymous pull.");
-                return await DownloadManifestInternalAsync(anonymousAccess: true);
+                Trace.WriteLine($"Anonymous authetncation failed with status code {requestedFailedException.Status}. Retrying with authenticated client.");
             }
-            catch (CredentialUnavailableException)
+            catch (Exception exception)
             {
-                // Fall back to anonymous client.
-                Trace.WriteLine($"Authenticated attempt to pull artifact for module {artifactReference.FullyQualifiedReference} failed due to missing login step. Fallback to anonymous pull.");
-                return await DownloadManifestInternalAsync(anonymousAccess: true);
+                Trace.WriteLine($"Anonymous authentication failed with unexpected exception {exception.Message}. Retrying with authenticated client.");
             }
+
+            // Fall back to authenticated client.
+            return await DownloadManifestInternalAsync(anonymousAccess: false);
         }
 
         public async Task PushArtifactAsync(