[Kernel][Type Widening] 8/ refactor collation parsing/setting not be intertwined with type parsing

[emkornfield]

🥞 Stacked PR

Use this link to review incremental changes.

• stack/tw_type_changes [Files changed]
  • stack/tw_type_changes_to_field_metadata [Files changed]
    • stack/tw_type_changes_to_field_metadata_impl [Files changed]
      • stack/tw_serde_refactor [Files changed]
        • stack/add_type_change_parsing [Files changed]
          • stack/tw_upgrade_downgrade [Files changed]

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Which Delta project/connector is this regarding?

• [ ] Spark
• [ ] Standalone
• [ ] Flink
• [x] Kernel
• [ ] Other (fill in here)

Description

This refactors the population of collation on StringTypes to be separate from parsing. This simplifies flows/arguments or parsing and consolidates the logic in a single place using StreamIterable.

How was this patch tested?

Existing tests.

Does this PR introduce any user-facing changes?

No.