[branch-2.0][fix](multi-table) fix unknown source slot descriptor when load multi table (#25762)

[sollhui]

Proposed changes

fix unknown source slot descriptor when load multi table (#25762)

Further comments

If this is a relatively large or complex change, kick off the discussion at dev@doris.apache.org by explaining why you chose the solution you did and what alternatives you considered, etc...

[sollhui]

run buildall

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[doris-robot]

TeamCity be ut coverage result:
Function Coverage: 38.25% (7933/20742)
Line Coverage: 30.05% (64139/213466)
Region Coverage: 29.27% (33228/113539)
Branch Coverage: 25.08% (17070/68064)
Coverage Report: http://coverage.selectdb-in.cc/coverage/ea7d1269b4f3a47a148bb4a70ef9b58c2d939386_ea7d1269b4f3a47a148bb4a70ef9b58c2d939386/report/index.html

[doris-robot]

(From new machine)TeamCity pipeline, clickbench performance test result:
the sum of best hot time: 49.47 seconds
stream load tsv: 575 seconds loaded 74807831229 Bytes, about 124 MB/s
stream load json: 20 seconds loaded 2358488459 Bytes, about 112 MB/s
stream load orc: 65 seconds loaded 1101869774 Bytes, about 16 MB/s
stream load parquet: 31 seconds loaded 861443392 Bytes, about 26 MB/s
insert into select: 29.6 seconds inserted 10000000 Rows, about 337K ops/s
storage size: 17162293551 Bytes

[sollhui]

run buildall

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[doris-robot]

TeamCity be ut coverage result:
Function Coverage: 38.24% (7931/20742)
Line Coverage: 30.03% (64110/213466)
Region Coverage: 29.25% (33214/113539)
Branch Coverage: 25.07% (17066/68064)
Coverage Report: http://coverage.selectdb-in.cc/coverage/0a1b40a645914a6facfc0c555ced656affa1b638_0a1b40a645914a6facfc0c555ced656affa1b638/report/index.html

[doris-robot]

(From new machine)TeamCity pipeline, clickbench performance test result:
the sum of best hot time: 49.12 seconds
stream load tsv: 588 seconds loaded 74807831229 Bytes, about 121 MB/s
stream load json: 20 seconds loaded 2358488459 Bytes, about 112 MB/s
stream load orc: 65 seconds loaded 1101869774 Bytes, about 16 MB/s
stream load parquet: 32 seconds loaded 861443392 Bytes, about 25 MB/s
insert into select: 29.3 seconds inserted 10000000 Rows, about 341K ops/s
storage size: 17167718753 Bytes