[Bug] doris backup error

### Search before asking

- [x] I had searched in the [issues](https://github.com/apache/doris/issues?q=is%3Aissue) and found no similar issues.

### Version

doris-4.0.6

### What's Wrong?

Server error: `ERROR 1105 (HY000): errCode = 2, detailMessage = Unknown system variable 'ignore_backup_tmp_partitions',the similar variables are {'ignore_split_type', 'ignore_shape_nodes', 'partition_topn_max_partitions'}'
SQL text omitted from user-facing error; enable debug SQL diagnostics for a redacted statement.

i try to EXCLUDE and add conf to ignore_backup_tmp_partitions fe, It still isn't taking effect

### What You Expected?

deal with next release

### How to Reproduce?

_No response_

### Anything Else?

_No response_

### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [x] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)

Start by searching the Doris source for `ignore_backup_tmp_partitions` and the backup or EXCLUDE handling, since no file, test, or reproduction steps are provided. Reproduce the ERROR 1105 case on doris-4.0.6; done means identifying why the setting is unknown or ignored and covering the corrected behavior with a test.

Written by the indexing model from the issue text.