Do not initiate MBB when internet is validated on lingering secondary

Fix a bug where MBB happens twice. After the initial MBB wifi-to-wifi
switch is complete, MBB should not trigger again if internet gets
validated on the lingering secondary STA.

Bug: 226675850
Test: atest com.android.server.wifi
Change-Id: Ife734efea94ae88561424825494639c848253760
2 files changed