[providers] Fix load method on LoadableEntitySchemaProvider

If the schema is loaded, the load methods returns now an empty schema.
4 jobs for topic/default/bugfix in 5 minutes and 1 second (queued for 2 minutes and 26 seconds)
Status Job ID Name Coverage
  Deps
passed Deps #29631

00:01:43

 
  Test
passed CanBuild #29634

00:01:25

passed Format #29633

00:01:08

passed Lint #29632

00:00:43