WifiConfigManager: Don't reset the userId on user stop

Couple of fixes in user stop handling:
a) Only clear the network data belonging to the user that is stopped.
b) Don't reset the user Id on stop. It will be done in the user switch
handling.

Bug: 65939780
Test: Unit tests
Change-Id: Ia3ab033d893009cfd8019ee27d52a490a8040438
2 files changed