Add additional dump information for UnderlyingNetworkTracker

This change adds additional dump information to facilitate the
resolution of bug reports.

Additionally, this method cleans up dump formatting.

Bug: 188842647
Test: atest FrameworksVcnTests
Test: adb shell dumpsys vcn_management
Change-Id: I5ce7fe05eb21a89c2034079223ef44f05db2a087
Merged-In: I5ce7fe05eb21a89c2034079223ef44f05db2a087
(cherry picked from commit 02cb0d7b)