Previously, customizers loaded from spring.factories were called
using LambdaSafe. This resulted in customizers with a generic type
more specific than Object being ignored. A customizer loaded from
the logging.structured.json.customizer property was not affected as
it was called directly rather than through LambdaSafe.
This commit aligns the way in which customizers loaded from
spring.factories are called with the way in which any customizer
specified using the logging.structured.json.customizer property is
called.
Closes gh-43312
a1c1e32947