test(studio): bank opening a film at 15 thumbnail requests, one per composition

Author: miguel-heygen

packages/studio/tests/e2e/perf-ceilings.json

@@ -1,11 +1,11 @@
 {
   "studio-open": {
-    "browser": "153",
+    "browser": "154",
     "counts": {
       "thumbnailRenders": 14,
       "total.frameNavigations": 7,
       "total.requests.document": 2,
-      "total.requests.thumbnail": 22
+      "total.requests.thumbnail": 15
     },
     "raised": {
       "total.requests.thumbnail": "#4401 shows a cached frame-0 poster while the preview boots: a cache-only ask that misses on a fresh open, then a render of that poster for the next open (+2 requests)"