Here https://mvnrepository.com/artifact/org.mongodb.kafka/mongo-kafka-connect/1.5.0 it shows that it needs avro and mongodb-driver-sync dependencies
I do not see any org.avro classes in mongo-kafka-1.5.0-all.jar … are you sure all of them are in the -all.jar?
no output for command jar tvf mongo-kafka-1.5.0-all.jar | grep avro
Here one line from error message output:
Caused by: org.glassfish.jersey.server.ContainerException: java.lang.NoClassDefFoundError: org/apache/avro/Schema