[omnibox][cr23] Static cache `kChromeRefresh2023Level`.

The param is read 3000 times on startup.
An additional 3000 times per browser window created.
And 200 times per omnibox keystroke.

That's large enough to have measurable omnibox performance movements.
1000 reads / keystroke have had 4-diamond movements in the past. 200
might have smaller than 4-diamond, but still significant, movements.

The read was introduced in crrev.com/c/4382808, which is rolling out
with m114. I'll try to merge this CL into m114. Otherwise, the m114
performance metrics might go off, and we won't know if it's real or just
the param read. m114 dev experiments are already underway, so their perf
metrics might be impacted regardless.

Change-Id: I0faca1880dad6640dd2af2519237bb755f7c6ce7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4497876
Reviewed-by: Keren Zhu <kerenzhu@chromium.org>
Reviewed-by: Peter Boström <pbos@chromium.org>
Commit-Queue: manuk hovanesian <manukh@chromium.org>
Auto-Submit: manuk hovanesian <manukh@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1138628}