Bug fix: resolve pagination error when changing pages on the Registry

[bobo495]

Purpose of the pull request

Fix a pagination error that occurs when switching pages on the Registry → Documents page while no sorting is applied.

console err log:

9876.6bb72816.async.js:1 Uncaught (in promise) Error: BizError: 
### Error querying database.  Cause: java.sql.SQLSyntaxErrorException: Unknown column 'a.undefined' in 'order clause'
### The error may exist in class path resource [mapper/DocumentMapper.xml]
### The error may involve defaultParameterMap
### The error occurred while setting parameters
### SQL: SELECT a.* FROM dinky_flink_document a WHERE 1 = 1 ORDER BY a.undefined ASC LIMIT ?,?
### Cause: java.sql.SQLSyntaxErrorException: Unknown column 'a.undefined' in 'order clause'
; bad SQL grammar []; nested exception is java.sql.SQLSyntaxErrorException: Unknown column 'a.undefined' in 'order clause'
    at 9876.6bb72816.async.js:1:84633
    at umi.d680b043.js:1199:5640
    at Generator.<anonymous> (umi.d680b043.js:1199:3053)
    at Generator.throw (umi.d680b043.js:1199:1801)
    at n (umi.d680b043.js:1198:3564)

Brief change log

• Fix pagination logic to handle unsorted document lists correctly
• Prevent page switching errors when sort parameters are missing or unset

Verify this pull request

This change added no new automated tests and can be verified as follows:

• Manually verified by accessing the Registry → Documents page without applying any sort
• Switched between different page numbers and confirmed no errors occur
• Verified normal pagination behavior when sorting is applied