[FEATURES] pod Label fluid.io/enable-injection missing should be treated same as fluid.io/enable-injection=false

[kingeasternsun]

What feature you'd like to add:

When CreateUpdatePodForSchedulingHandler Handle pod, should treats pod without Label fluid.io/enable-injection same as pod with fluid.io/enable-injection=false,just skip mutating the pod

Why is this feature needed:
In the k8s clusters of many companies, there are many other services that do not require fluid.
If CreateUpdatePodForSchedulingHandler could treats pod without Label fluid.io/enable-injection same as pod with Labelfluid.io/enable-injection=false, these services could continue work without the need for additional modifications that add labels fluid.io/enable-injection=false to the pod of services

[TrafalgarZZZ]

@kingeasternsun Thanks for the issue. Which version of Fluid are you using? We have now turned to use objectSelector instead of the namespaceSelector``fluid.io/enable-injection. You can trigger webhook mutations at pod-level with pod.metadata.labels={"fuse.serverful.fluid.io/inject": "true"} or pod.metadata.labels={"serverless.fluid.io/inject": "true"}. Please see here and here for detailed examples.