When inserting into a compressed chunk with an ON CONFLICT clause, and
there is a concurrent recompression of the chunk, an error can occur
due to a failed lookup of the compressed chunk.
The error happens because the chunk information is re-read from an
outdated cache holding a compressed chunk ID that no longer exists
after the chunk was recompressed (recompression effectively removes
the compressed chunk and creates it again).
Fix this issue by ensuring that the insert path only uses up-to-date
chunk metadata read _after_ the lock on the chunk was taken.
