AllOpen plugin makes the properties all-open, but the annotation class
is left closed, because allopen for k2 literally checks
`classKind == CLASS`.
Since the properties are open, a
`NON_FINAL_MEMBER_IN_FINAL_CLASS` diagnostic is reported for them. It's
positioning strategy seeks for the explicit `open` modifier which is
not present.
The added test should not crash the compiler.
^KT-54260 Fixed
Ilya Kirillov