[C++] Nested RUN_END_ENCODED arrays (a REE of a REE) should be considered invalid

### Describe the bug, including details regarding any error messages, version, and platform.

Since they don't bring any data compression benefit and would complicate kernels dealing with REEs by a lot.

### Component(s)

C++

The issue names no file or test. Start by locating the C++ validation and handling for nested RUN_END_ENCODED arrays, then add coverage showing that a REE of a REE is rejected. Done means nested REE input is consistently considered invalid.

Written by the indexing model from the issue text.