Let rawler decode a linear DNG wider than 16 700 pixels

rawler's allocation guard is sized in samples but worded in pixels, and
a linear DNG passes width × 3. A 22927 × 8966 Lightroom panorama was
refused as ">50000 px wide", and develop fell back silently to the
embedded preview. Route rawler through third_party with the guard at
1.5 G samples and 200 000 per axis.

Cargo.toml

@@ -284,3 +284,4 @@ codegen-units = 1
 [patch.crates-io]
 wgpu-hal = { path = "third_party/wgpu-hal-29.0.4" }
 i-slint-renderer-skia = { path = "third_party/i-slint-renderer-skia-1.17.1" }
+rawler = { path = "third_party/rawler-0.7.2" }