MONGOID-5839 Fix eager-loading from STI subclasses #3879

Job	Run time
ruby-3.3 drv:current db:7.0 rails: fle: replica_set	6s
ruby-3.2 drv:current db:6.0 rails: fle: replica_set	6s
ruby-3.1 drv:current db:6.0 rails: fle: replica_set	5s
ruby-3.0 drv:stable db:6.0 rails: fle: replica_set	6s
ruby-3.3 drv:current db:7.0 rails:8.0 fle:helper server	12m 16s
ruby-3.2 drv:current db:7.0 rails:7.2 fle:helper server	10s
ruby-3.2 drv:current db:7.0 rails:7.1 fle:helper server	11s
ruby-3.1 drv:current db:7.0 rails:7.0 fle:helper server	5s
ruby-3.1 drv:current db:6.0 rails:6.1 fle:helper server	6s
ruby-3.0 drv:current db:6.0 rails:6.1 fle:helper server	5s
ruby-3.0 drv:current db:6.0 rails:6.0 fle:helper server	7s
jruby-9.4 drv:current db:6.0 rails:6.0 fle:helper server	11s
ruby-3.1 drv:current db:5.0 rails: fle: replica_set	6s
ruby-2.7 drv:current db:4.4 rails: fle: replica_set	8s
	13m 48s

Provide feedback