Cancel add index job in none state may leak

[tangenta]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

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

Should not report "ingest backfill is already in use by another DDL job".

3. What did you see instead (Required)

"ingest backfill is already in use by another DDL job".

4. What is your TiDB version? (Required)

c8caa48