Close ImportProcessPrx instances (Fix #12233)

Once upload is completed, the import process instance should
be closed. The `HandlePrx` which is returned will continue
functioning.
Use dsFactory.getLogger in OMEROGateway
Merge pull request #2413 from joshmoore/rebased/develop/12233-close-importproc

Close ImportProcessPrx instances (Fix #12233) (rebased onto develop)