Fix ImageReplyBodyView test flake (#33974)

* Fix aspect ratio in ImageReplyBodyView story

* De-flake blurhash story via per-story failureThreshold

Revert the aspectRatio change (it produced byte-identical blurhash output,
so it did not address the flake, and only churned the with-banner baseline)
and instead allow a small per-story failureThreshold on LoadingWithBlurhash.
The blurhash <canvas> rasterizes to one of two ~33px-apart variants per run;
this tolerates that benign jitter while keeping the strict 3px elsewhere.

packages/shared-components/src/room/timeline/event-tile/body/MImageReplyBodyView/ImageReplyBodyView.stories.tsx

@@ -75,6 +75,13 @@ export const LoadingWithBlurhash: Story = {
     args: {
         placeholder: ImageReplyBodyViewPlaceholder.BLURHASH,
     },
+    // The blurhash <canvas> rasterizes to one of two ~33px-apart variants per run;
+    // tolerate that benign jitter rather than flake against the strict 3px default.
+    parameters: {
+        snapshot: {
+            failureThreshold: 100,
+        },
+    },
 };
 
 export const AnimatedPreview: Story = {