Delete another library obsolete since 23.2

This was missed in a previous commit to remove obsolete libraries.
Its deletion was already announced in NEWS.

* lisp/obsolete/levents.el: Delete file.  This library has been
obsolete since 23.2.
1 job for master in 15 minutes and 26 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
failed #6062
test-all

00:15:26

 
Name Stage Failure
failed
test-all Test
  GEN      ../../lisp/international/uni-combining.el
GEN ../../lisp/international/uni-comment.el
GEN ../../lisp/international/uni-decimal.el
GEN ../../lisp/international/uni-decomposition.el
GEN ../../lisp/international/uni-digit.el
GEN ../../lisp/international/uni-lowercase.el
GEN ../../lisp/international/uni-mirrored.el
GEN ../../lisp/international/uni-name.el
ERROR: Job failed: exit code 137