reorg handle not resumed after changing DDL owner

[tangenta]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

1. Modify column on a large table, trigger a reorganization.
2. Switch DDL owner.

2. What did you expect to see? (Required)

Another TiDB instance should pick up the modifying column work.

3. What did you see instead (Required)

The entire modifying column is restarted.

4. What is your TiDB version? (Required)

v8.1.1