Fix compositeBoundsReduced_ not being reset for full-image decompress

When setDecompressRegion is called with region (0,0,0,0) (full image),
it returns early before the block that was resetting compositeBoundsReduced_.
This caused successive decompress calls (e.g. reading different bands) to
incorrectly skip composite bounds reduction, producing wrong pixel values.

Move the reset to the top of the function so it always executes.

Author: Grok Compression

src/lib/core/codestream/decompress/CodeStreamDecompress.cpp

@@ -1227,6 +1227,7 @@ std::function<void()> CodeStreamDecompress::postMultiTile(ITileProcessor* tilePr
 
 bool CodeStreamDecompress::setDecompressRegion(RectD region)
 {
+  compositeBoundsReduced_ = false;
   auto image = headerImage_;
   auto imageBounds = headerImage_->getBounds();
 
@@ -1258,7 +1259,6 @@ bool CodeStreamDecompress::setDecompressRegion(RectD region)
       region.x1 *= scale;
       region.y1 *= scale;
     }
-    compositeBoundsReduced_ = false;
     Rect16 tilesToDecompress;
     auto canvasRegion = Rect32((uint32_t)region.x0 + image->x0, (uint32_t)region.y0 + image->y0,
                                (uint32_t)region.x1 + image->x0, (uint32_t)region.y1 + image->y0);