Event Log Sources - indicate dynamic date detection disabled

Update the indexing section of each of the Windows Event Log-based sources indicating that dynamic date detection has been disabled for these indices. The sources are:

- Windows
- PowerShell
- Sysmon
- Windows DNS

This is related to the work done in https://github.com/Graylog2/graylog-project-illuminate/issues/2798

Search the documentation for the Windows, PowerShell, Sysmon, and Windows DNS source pages, then read each indexing section. Update all four sections to state that dynamic date detection is disabled for these indices; completion means each listed source reflects that status consistently.

Written by the indexing model from the issue text.