Revert "[Wi-Fi] Add proto fields for Openroaming network."

This reverts commit d64e9452.

Reason for revert:
Those two metrics are added for Openroaming service, but they can not be used finally, so remove them.

Bug: 146669261
Test: No, just remove proto fields.
Change-Id: I601927c443b13a5d2d52e60ad4c910204156a102