[Xon] Redis Cache 2.18.11

• Replace use of serialize() with json_encode() when computing hash for cached thread list totals
• Fix changing the serializer would cause site to unexpectedly fail until the cache was manually cleared.
  This causes the code to attempt to use php unserialize() or igbinary_unserialize() if the other fails. Only works if igbinary extension is installe

• Fix XF2.3 compatibility where "Call to undefined method Symfony\Component\Cache\Adapter\RedisAdapter::getRedis()" could occur depending on exact caching configuration
• Fix sentinel high-availability support could sometimes try to communicate with a "down" replica due to a missing check
• Displaying valkey version information in redis stats block

Fix showing an empty "maxmemory" redis info section in admincp

• Fix incorrect order of applying TLS options for a connection and using redis password authentication when not using phpredis extension
• Fix dragonflydb support when displaying redis stats block around memory usage
  • Note; full dragonflydb functionality has not been tested

• 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