api: Only return a Platform when relevant information is available

I noticed that we could return a Platform that has no information filled
in. This doesn't look like it would cause any problems, but it would be
confusing. Fix the handler to only append to this slice when the
Platform is not empty.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>

api/server/router/distribution/distribution_routes.go

@@ -122,7 +122,7 @@ func (s *distributionRouter) getDistributionInfo(ctx context.Context, w http.Res
 		var platform v1.Platform
 		if err == nil {
 			err := json.Unmarshal(configJSON, &platform)
-			if err == nil {
+			if err == nil && (platform.OS != "" || platform.Architecture != "") {
 				distributionInspect.Platforms = append(distributionInspect.Platforms, platform)
 			}
 		}