fix: handle empty channel data

Some layers (e.g. gradient fill layers) may have empty channel data.
Previously, attempting to skip over the scan lines in such channels
resulted in buffer overflow (RangeError).
Let's avoid this by limiting the skip amount to the size of the channel
data. This ensures that empty channels cannot be "skipped" at all.

Note: This appears to render the layer as a 1x1 empty image.
Although this is not ideal, we can't do anything about it. Synthesizing
a layer image from its gradient metadata is currently beyond our scope.

packages/psd/src/sections/LayerAndMaskInformation/readLayerRecordsAndChannels.ts

@@ -247,7 +247,10 @@ function readLayerChannels(
         // Compressed bytes per scanline are encoded at the beginning as 2 bytes per scanline
 
         const bytesPerScanline = fileVersionSpec.rleScanlineLengthFieldSize;
-        const skip = scanLines * bytesPerScanline;
+        // Do not attempt to skip more than the length of the channel data.
+        // This is needed because some layers (e.g. gradient fill layers) may
+        // have empty channel data (channelDataLength === 0).
+        const skip = Math.min(channelDataLength, scanLines * bytesPerScanline);
         const data = new Uint8Array(
           channelData.buffer,
           channelData.byteOffset + skip,