[Xon] Redis Cache 2.18.6

• Fix possible incorrect query generation when caching forum totals with custom 3rd party time-conditions

• Fix caching forum totals support when a date limit filter or 'Thread list date limit' is set on the forum
• Improve compatibility with Known Bots add-on
• Add caching for "Online statistics" block as this query becomes unexpectedly expensive as the user-count skyrockets

• php 8.4+ compatibility fixes
• For XF2.3.4+, check "View server information" admin permission when viewing redis information

• Fix deleteMultiple() method for XF2.3 (not used by stock XF)

• Fix XF2.3 support for some add-ons depending on extended redis functionality

• Restore XF2.1 support

• Fix high availability support where css updates would be sent to a possible readonly replica instead of the writable instance

NA

• High avaliability config default change:
  • Change default value for retry_reads_on_primary config option to true as this guards against unexpected replication delays
• Remove unexpected differences for XF2.2 and XF2.3 support (only tested on XF2.2)
• When displaying redis version, include the redis varaint type.
  • Known variants are keydb & dragonflydb.
  • Dragonflydb does not appear to support IO stats at the moment

• Fix helper code to expire/purge redis keys did not support non-main cache backends.
  • If using a separate caching backend for css, old styling was not actively expired as expected, resulting in higher memory usage
  • If 3rd party code uses expireCacheByPattern/purgeCacheByPattern function, the new nullable 'cache' parameter should be used