fix: support sourcemaps stored in chunk.map

[RodionKorneev]

Fix sourcemap detection for Vite builds.

In some Vite/Rollup configurations sourcemaps are not emitted as separate
assets but attached to chunks via the map property:

{
  type: 'chunk', 
  fileName: 'chunk.js', 
  map: {...}
  // other props
}

The current implementation only checks for asset entries ending with .map,
which causes sourcemaps to be skipped.

This change adds support for chunk-based sourcemaps while preserving the
existing behaviour.

[Copilot]

Pull request overview

Adds support for Vite/Rollup configurations where sourcemaps are attached directly to chunk.map (instead of being listed as separate .map assets in the bundle metadata), so the plugin can still discover and upload sourcemaps.

Changes:

• Update sourcemap filename detection to also consider chunk.map entries.
• Preserve existing detection of .map assets.

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