ui: Refactor Wattson warning logic and improve config checks

[runpinglai-creator]

This commit is the improvement of
#3012, which was reverted because of following reasons:

Reason: Two-fold:
1) Wattson is not enough of a "core Perfetto feature" that we need to
   have the tracks show up on every trace type. For example, right now,
   this will show up on Linux traces, heap profiles heap dumps etc.
   Unconditionally showing tracks when you have no data is not OK: the
   user may have very intentially not enabled your stuff, warning them
   every time and using valuable real estate is unacceptable. If we want
   something like this, we should add something to a section on the info
   and stats page but even then, we need to scope it to "if the person
   expected Wattson to be enabled": if they don't care about it, it
   should not bother them
2) Tried on a random trace and the warnings just appeared broken. If
   clicked on the warning, nothing showed up.

Improvement to above suggestions:

1. It makes sense that showing Wattson unconditionally is not
   ok. Not everyone is using Perfetto for Wattson. Therefore this change
   will only make Wattson warnings and blank tracks visible to "Wattson
   users" who have enabled Wattson Markers. Enabling the marker is the
   sign of user's intention of using Wattson. If a user didn't enable the
   marker, no wattson track or warning will be bother the user.
2. Tested ok. Right now this code change is only applicable to
   power/cpu_frequency (checking both atrace, ftrace, and cpu_freq_ms)
   and devfreq/devfreq_frequency.

Test: Local Perfetto UI Test
Bug: 444535474

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