[Feature](struct-type) Add implicitly cast for struct-type

[xy720]

Proposed changes

Issue Number: close #16547

Problem summary

For example, currently not support insert {1, 'a'} into struct<f1:tinyint, f2:varchar(20)>
This commit will support implicitly cast the char type in the struct to varchar.

Add implicitly cast for struct-type.

Checklist(Required)

1. Does it affect the original behavior:
   • Yes
   • No
   • I don't know
2. Has unit tests been added:
   • Yes
   • No
   • No Need
3. Has document been added or modified:
   • Yes
   • No
   • No Need
4. Does it need to update dependencies:
   • Yes
   • No
5. Are there any changes that cannot be rolled back:
   • Yes (If Yes, please explain WHY)
   • No

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...

[hello-stephen]

TeamCity pipeline, clickbench performance test result:
the sum of best hot time: 35.5 seconds
stream load tsv: 487 seconds loaded 74807831229 Bytes, about 146 MB/s
stream load json: 36 seconds loaded 2358488459 Bytes, about 62 MB/s
stream load orc: 69 seconds loaded 1101869774 Bytes, about 15 MB/s
https://doris-community-test-1308700295.cos.ap-hongkong.myqcloud.com/tmp/20230210174104_clickbench_pr_94167.html

[cambyzju]

LGTM

[github-actions]

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

[github-actions]

PR approved by anyone and no changes requested.