[harmonyhub] Fix reliability issues (#13702)

[harmonyhub] Fix reliability issues (#13702)

* Fix compiler info

Unsafe interpretation of method return type as '@NonNull' based on the receiver type 'java.util.Enumeration<java.net.@NonNull NetworkInterface>'. Type 'java.util.Enumeration<E>' doesn't seem to be designed with null type annotations in mind

* Improve robustness of job rescheduling and handler disposal

Handler tried updating thing although the handler was already disposed

Fixes #13701

Signed-off-by: Jacob Laursen <jacob-github@vindvejr.dk>