pw_watch: Fix startup exception
pw_watch: Fix startup exception

A past CL (108730) introduced a better log rendering timer but
forgot to add that functionality to pw watch --fullscreen

Change-Id: I427909acb07e47f220640d6e5ff93c3060030d90
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/109713
Pigweed-Auto-Submit: Anthony DiGirolamo <4cc40125edc24ec5bc72df7917ea0b403ee8cebe@google.com>
Reviewed-by: Wyatt Hepler <cca3bedb37979eacd157a9bceb473582df8aea1e@google.com>
Commit-Queue: Auto-Submit <14637eda5603879df170705285bf30f5996692f0@pigweed.google.com.iam.gserviceaccount.com>

google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed