chore(deps): update dependency ubuntu to v26 (#3338)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/test.yml

@@ -43,7 +43,7 @@ jobs:
     name: Visual Regression
     # arm64 to match `scripts/visual.sh`, which cannot generate amd64 baselines
     # because Chromium segfaults under emulation on Apple Silicon.
-    runs-on: ubuntu-24.04-arm
+    runs-on: ubuntu-26.04-arm
     permissions:
       contents: read