pimd: (*,G) Prune processing doesn't remove SGRpt ifchannel

pimd: (*,G) Prune processing doesn't remove SGRpt ifchannel

problem :
=========
When (*,G) prune received where we have SGRpt state,
ifchannel goes to NO_INFO state and doesn't get removed.

Root cause :
============
During the processing of (*,G) prune, we are not removing the
ifchannel on PruneTmp or PrunePendingTmp state.

Fix :
=====
In that scenario, stop joinExpiry timer and delete the ifchannel.

issue #7347

Co-authored-by: Saravanan K <saravanank@vmware.com>
Signed-off-by: vishaldhingra <vdhingra@vmware.com>