set module eviction context flag only in masters (#8631)
set module eviction context flag only in masters (#8631)

REDISMODULE_CTX_FLAGS_EVICT and REDISMODULE_CTX_FLAGS_MAXMEMORY
shouldn't be set when the module is run inside a replica that doesn't do eviction.

one may argue that the database is under eviction (the master does eviction and sends DELs to the replica).
but on the other hand, we don't really know the master's configuration.
all that matters is if the current instance does evictions or not.
JackieXie168/redis,JackieXie168/redis,JackieXie168/redis,JackieXie168/redis