fix: correct OfflineProgressStatus TypeScript type and TileRegionPackState typo

[PHILLIPS71]

Description

Corrects the OfflineProgressStatus TypeScript type, which had several inaccuracies compared to what the native modules (Android/iOS) actually emit:

• state was typed as number but is always a string, so it was changed to a strict union: 'invalid' | 'inactive' | 'active' | 'complete' | 'unknown'
• Removed phantom fields completedTileCount and completedTileSize that were never emitted by native code
• Added missing fields that native always emits: erroredResourceCount, loadedResourceSize, loadedResourceCount
• Converted to a discriminated union on percentage to accurately model the two distinct payload shapes: one with full progress data and one emitted when a pack exists but has not yet started loading (percentage is null and resource counts are absent)
• Narrowed OfflinePackDownloadState values in RNMBXModule.ts from string | number to string, consistent with what native actually sends
• Fixed a typo in TileRegionPackState.UNKNOWN on Android: "unkown" to "unknown"

Checklist

• I've read CONTRIBUTING.md
• I updated the doc/other generated code with running yarn generate in the root folder
• I have tested the new feature on /example app.
  • In V11 mode/ios
  • In New Architecture mode/ios
  • In V11 mode/android
  • In New Architecture mode/android
• I added/updated a sample - if a new feature was implemented (/example)

Screenshot OR Video

N/A type-only changes with one runtime string correction on Android.

Component to reproduce the issue you're fixing

// state was typed as number but native always emits a string
offlineManager.subscribe(pack, (pack, status) => {
  console.log(typeof status.state); // was typed as number, actually "active" | "complete" | etc.
  console.log(status.completedTileCount); // phantom field was always undefined at runtime
});