core: refactor VectorMLTTileData behind impl

[louwers]

Preparation for alternate implementation of VectorMLTTileData.

GPT 5.6 used for refactor.

[github-actions]

Bloaty Results 🐋

Compared to main

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  +0.0% +13.1Ki  +0.0% +4.29Ki    TOTAL

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/bloaty-results/pr-4427-compared-to-main.txt

Compared to d387090 (legacy)

    FILE SIZE        VM SIZE    
 --------------  -------------- 
   +55% +63.3Mi  +472% +28.2Mi    TOTAL

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/bloaty-results/pr-4427-compared-to-legacy.txt

[github-actions]

Benchmark Results ⚡

Benchmark                                                          Time             CPU      Time Old      Time New       CPU Old       CPU New
-----------------------------------------------------------------------------------------------------------------------------------------------
OVERALL_GEOMEAN                                                 +0.0049         +0.0051             0             0             0             0

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/benchmark-results/pr-4427-compared-to-main.txt

[github-actions]

Bloaty Results (iOS) 🐋

Compared to main

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  +0.1% +17.0Ki  +0.1% +16.0Ki    TOTAL

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/bloaty-results-ios/pr-4427-compared-to-main.txt