[fix](be) Fix missing decimal precision and scale for legacy decimal data (#65419)

[jacktengg]

Issue Number: close #xxx

Pick #65419

Related PR: #26572, #63569

Problem Summary:

Segments written before decimal ColumnMetaPB precision and scale were persisted can miss precision and scale for decimal types in metadata . Regular columns, complex decimal children may then build decimal DataType instances without the logical precision/scale from TabletSchema, and result in error "Wrong precision 0, min: 1, max: 76". This change centralizes decimal metadata recovery from TabletSchema, applies it before ColumnReader/DataType creation.

Fix reading legacy decimal whose segment metadata is missing decimal precision and scale.

• Test

  • Regression test
  • Unit Test
  • Manual test (add detailed scripts or steps below)
  • No need to test or manual test. Explain why:

• This is a refactor/code format and no logic has been changed.
  - [ ] Previous test can cover this change. - [ ] No code files have been changed. - [ ] Other reason

• Behavior changed:

  • No.
  • Yes.

• Does this need documentation?

  • No.

• Yes.

• Confirm the release note

• Confirm test cases

• Confirm document

• Add branch pick label

What problem does this PR solve?

Issue Number: close #xxx

Related PR: #xxx

Problem Summary:

Release note

None

Check List (For Author)

• Test

  • Regression test
  • Unit Test
  • Manual test (add detailed scripts or steps below)
  • No need to test or manual test. Explain why:
    • This is a refactor/code format and no logic has been changed.
    • Previous test can cover this change.
    • No code files have been changed.
    • Other reason

• Behavior changed:

  • No.
  • Yes.

• Does this need documentation?

  • No.
  • Yes.

Check List (For Reviewer who merge this PR)

• Confirm the release note
• Confirm test cases
• Confirm document
• Add branch pick label

[hello-stephen]

Thank you for your contribution to Apache Doris.
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Please clearly describe your PR:

1. What problem was fixed (it's best to include specific error reporting information). How it was fixed.
2. Which behaviors were modified. What was the previous behavior, what is it now, why was it modified, and what possible impacts might there be.
3. What features were added. Why was this function added?
4. Which code was refactored and why was this part of the code refactored?
5. Which functions were optimized and what is the difference before and after the optimization?

[jacktengg]

run buildall

[hello-stephen]

BE UT Coverage Report

Increment line coverage 89.13% (41/46) 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	54.81% (20955/38234)
Line Coverage	38.25% (200208/523388)
Region Coverage	34.72% (157232/452911)
Branch Coverage	35.66% (68609/192372)