compress: fix an internal error when a specific debug log is enabled
While iterating over the recent 69684e16d8,
series I shot myself in the foot by defining `algorithm_to_name(algorithm::none)`
to be an internal error, and later calling that anyway in a debug log.
(Tests didn't catch it because there's no test which simultaneously
enables the debug log and configures some table to have no compression).
This proves that `algorithm_to_name` is too much of a footgun.
Fix it so that calling `algorithm_to_name(algorithm::none)` is legal.
In hindsight, I should have done that immediately.
Fixes#23624
Fix for recently-added code, no backporting needed.
Closesscylladb/scylladb#23625
* github.com:scylladb/scylladb:
test_sstable_compression_dictionaries: reproduce an internal error in debug logging
compress: fix an internal error when a specific debug log is enabled
(cherry picked from commit 746382257c)
7673a17365