test(trace-explorer): Pin trace timestamps in the past

[Zylphrex]

When it's close to midnight, the timeout tests tends to fail because it actually finds the trace since it was not far enough in the past.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.01%. Comparing base (88ac464) to head (c15abd3).
Report is 9 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #73485   +/-   ##
=======================================
  Coverage   78.01%   78.01%           
=======================================
  Files        6634     6634           
  Lines      296733   296749   +16     
  Branches    51108    51110    +2     
=======================================
+ Hits       231490   231514   +24     
+ Misses      58855    58849    -6     
+ Partials     6388     6386    -2     

see 11 files with indirect coverage changes