Move CaptivePortalProbeResult to its own file

This is necessary to resolve visibility issues for the next change.

Bug: b/79499239
Test: runtest frameworks-net
Merged-In: Ia48b32307a51a66f2672d7112f71166dd6db41b1
Merged-In: I5df7ee9f16bc6be4f02353d40a843a383dd4cbd9
(Clean cherry-pick of pi-dev I50bc96afe6ae88c8f58a693f0a4e821f1f9b3299)

Change-Id: I3c416c1a91ebfdf914fd528ff8ab73e3eb490562
3 files changed