We have identified a race condition in __wti_conn_dhandle_outdated. 

session->dhandle can be freed or cleared by a concurrent thread between the time it is found using __wt_conn_dhandle_find and the time it is acquired or accessed.

This can lead to a error when the dhandle is accessed.

Steps to Reproduce

1. Run test/format in a multi-node configuration with disaggregated storage enabled.
2. Modify src/conn/conn_dhandle.c, inside _wti_conn_dhandle_outdated, to insert a sleep after _wt_conn_dhandle_find and before WT_DHANDLE_ACQUIRE, to widen the race window.
3. Run the test.

How to run multi node (test/format)

cd build/test/format
./format_disagg_multi.sh