[WifiNetworkSelector] User-selected network is sufficient for a while

Skip autojoin for the first few seconds of a user-initiated connection.

This avoids early disconnection before the user has had a chance to
respond to a no-internet or limited internet dialog, and allows some
additional time for validation to succeed in case the dialog is not
noticed.

Bug: 130766237
Test: atest WifiNetworkSelectorTest
Change-Id: I0a06135afef1876af385829d131a0e52b1884900
2 files changed