Cell Broadcast (CBS) is according to bm818-tool always disabled after restart

Steps to reproduce:

1. Enable CBS in bm818-tool
2. Exit the bm818-tool
3. Shut down the Librem 5
4. Start the Librem 5
5. Open the bm818-tool

Actual behavior: bm818-tool shows that CBS is disabled.

Expected behavior: bm818-tool shows that CBS is enabled.