fix(promtail): windows forward event crash

[wildum]

What this PR does / why we need it:

In Alloy we are still using the win_eventlog pkg from Promtail and a user reported that some windows events would make Alloy crash during ingestion (grafana/alloy#2616).

During the investigation, I found out that this code was taken from Telegraf and that this is a problem that they encountered and solved via influxdata/telegraf#12375.

I ported the fix to my local loki and built a custom Alloy version with it. The user tested and reported that the bug was solved: grafana/alloy#2616 (comment)

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
• Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• If the change is deprecating or removing a configuration option, update the deprecated-config.yaml and deleted-config.yaml files respectively in the tools/deprecated-config-checker directory. Example PR