WT-18369 fixed a bug in step-up where stable tables were missing certain configuration (such as block_manager and block_compressor). The fix prevents new occurrences but cannot repair tables already affected.

Add a connection statistic, disagg_stable_config_suspect_tables, counting stable tables whose shared metadata indicates they may have been affected by WT-18369. This will allow us to identify clusters that require remediation.

Before implementing the statistic, establish a reliable detection criterion. block_manager and block_compressor can legitimately have default values, so these two settings alone are not evidence of WT-18369.

Ensure the scanning of the shared metadata is performed in such a time that it does not adversely impact startup time and runtime performance.