CI: Update Emscripten Docker image to 3.1.51 (#3907)

Author: kleisauke

.github/workflows/ci.yml

@@ -158,7 +158,7 @@ jobs:
       contents: write
     name: wasm32 - prebuild
     runs-on: ubuntu-22.04
-    container: "emscripten/emsdk:3.1.48"
+    container: "emscripten/emsdk:3.1.51"
     steps:
       - name: Checkout
         uses: actions/checkout@v4