[segmentation] Add validation for output config

Add detailed validation checks for output config. The prefs could have
stale or invalid output config. Validate it before parsing the config.

Bug: b/300280579
Change-Id: I9e0065e70807cdc986115cd2cb591d550ee3459d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4873228
Commit-Queue: Siddhartha S <ssid@chromium.org>
Reviewed-by: Salvador Guerrero Ramos <salg@google.com>
Cr-Commit-Position: refs/heads/main@{#1199273}