Fix EventLogger: Do not recreate class ids

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 55.55556% with 4 lines in your changes missing coverage. Please review.

Project coverage is 67.33%. Comparing base (f955f2f) to head (f07e7f2).

Files	Patch %	Lines
libsrc/pylith/utils/EventLogger.cc	55.55%	4 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #737 +/- ## ======================================= Coverage 67.33% 67.33% ======================================= Files 156 156 Lines 20085 20088 +3 ======================================= + Hits 13524 13527 +3 Misses 6561 6561 ``` | [Flag](https://app.codecov.io/gh/geodynamics/pylith/pull/737/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=geodynamics) | Coverage Δ | | |---|---|---| | [fullscale](https://app.codecov.io/gh/geodynamics/pylith/pull/737/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=geodynamics) | `56.61% <55.55%> (+<0.01%)` | :arrow_up: | | [libtests](https://app.codecov.io/gh/geodynamics/pylith/pull/737/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=geodynamics) | `23.77% <55.55%> (+0.01%)` | :arrow_up: | | [mmstests](https://app.codecov.io/gh/geodynamics/pylith/pull/737/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=geodynamics) | `35.93% <55.55%> (+<0.01%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=geodynamics#carryforward-flags-in-the-pull-request-comment) to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.