Bump mymindstorm/setup-emsdk from 14 to 15

Bumps [mymindstorm/setup-emsdk](https://github.com/mymindstorm/setup-emsdk) from 14 to 15.
- [Release notes](https://github.com/mymindstorm/setup-emsdk/releases)
- [Commits](6ab9eb1bda...667eb33f24)

---
updated-dependencies:
- dependency-name: mymindstorm/setup-emsdk
  dependency-version: '15'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/ubuntu.yml

@@ -256,7 +256,7 @@ jobs:
           egress-policy: audit
 
       - name: Install emscripten
-        uses: mymindstorm/setup-emsdk@6ab9eb1bda2574c4ddb79809fc9247783eaf9021 # v14
+        uses: mymindstorm/setup-emsdk@667eb33f24e84e7f362c16d8d7fff0629a73e15e # v15
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       - name: Get latest CMake and ninja
         uses: lukka/get-cmake@f176ccd3f28bda569c43aae4894f06b2435a3375 # v4.2.3