Slightly refactor latestEventsUpdater

[S7evinK]

In an attempt to make testing the latestEventsUpdater easier, some moving around of variables and method calls.

[codecov]

Codecov Report

Attention: Patch coverage is 52.38095% with 30 lines in your changes missing coverage. Please review.

Project coverage is 67.53%. Comparing base (9897959) to head (928f3a0).
Report is 5 commits behind head on main.

Files	Patch %	Lines
roomserver/internal/input/input_latest_events.go	52.38%	23 Missing and 7 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3272      +/-   ##
==========================================
- Coverage   67.54%   67.53%   -0.01%     
==========================================
  Files         521      521              
  Lines       47381    47384       +3     
==========================================
+ Hits        32002    32003       +1     
- Misses      11394    11397       +3     
+ Partials     3985     3984       -1     

Flag	Coverage Δ
unittests	52.81% <52.38%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.