clp-s: Nested timestamps result in incorrect mst node names

[gibber9809]

Bug

Ingesting records with nested timestamps using the --timestamp-key argument turns the key name in the last level of the MST into the fully qualified name. e.g. records like {"a": "ts": ...} will look like {"a": "a.ts": ...} when decompressed.

CLP version

e80cee0

Environment

Ubuntu focal clp image

Reproduction steps

1. Ingest a dataset with nested timestamps while using the --timestamp-key argument
2. Observe incorrect data upon decompression