[fix](es catalog) remove _default_ field when parsing mapping.

[qidaye]

Proposed changes

Issue Number: close #24780

Remove _default field, we do not parse _default_ mapping, only explicit mapping.
_default _mapping type is deprecated in 7.0 and removed in 8.0
see: https://www.elastic.co/guide/en/elasticsearch/reference/7.17/removal-of-types.html

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...

[qidaye]

run buildall

[doris-robot]

(From new machine)TeamCity pipeline, clickbench performance test result:
the sum of best hot time: 46.48 seconds
stream load tsv: 560 seconds loaded 74807831229 Bytes, about 127 MB/s
stream load json: 21 seconds loaded 2358488459 Bytes, about 107 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: 28.8 seconds inserted 10000000 Rows, about 347K ops/s
storage size: 17162212936 Bytes

[xiaokang]

LGTM

[github-actions]

PR approved by at least one committer and no changes requested.

[github-actions]

PR approved by anyone and no changes requested.

[qidaye]

run p0

[qidaye]

run buildall

[morningman]

LGTM

[doris-robot]

(From new machine)TeamCity pipeline, clickbench performance test result:
the sum of best hot time: 45.28 seconds
stream load tsv: 561 seconds loaded 74807831229 Bytes, about 127 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: 28.7 seconds inserted 10000000 Rows, about 348K ops/s
storage size: 17162083303 Bytes