Keep the scale and precision of type when creating mv

[EmmyMiao87]

Proposed changes

The DECIMAL, CHAR, VARCHAR have their own scale and precision in column.
The mv column should keep those scale and precision.

Fixed #4433
Change-Id: Ie288738a4356e60d11ea472dd274e54bc7ae6990

Types of changes

What types of changes does your code introduce to Doris?
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• Bugfix (non-breaking change which fixes an issue)
• [] New feature (non-breaking change which adds functionality)
• [] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [] Documentation Update (if none of the other choices apply)
• [] Code refactor (Modify the code structure, format the code, etc...)

Checklist

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• I have create an issue on (Fix #ISSUE), and have described the bug/feature there in detail
• Compiling and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• [] If this change need a document change, I have updated the document
• [] Any dependent changes have been merged

[morningman]

LGTM

[EmmyMiao87]

#4411