ci: run emscripten on Ubuntu 22.04

python3-selenium does not seem to work on Ubuntu 24.04

.github/workflows/create-test-plan.py

@@ -127,7 +127,7 @@ JOB_SPECS = {
     "android-cmake-lean": JobSpec(name="Android (CMake, lean)",             os=JobOs.UbuntuLatest,  platform=SdlPlatform.Android,     artifact="SDL-lean-android-arm64", android_abi="arm64-v8a", android_arch="aarch64", android_platform=23, lean=True, ),
     "android-mk": JobSpec(name="Android (Android.mk)",                      os=JobOs.UbuntuLatest,  platform=SdlPlatform.Android,     artifact=None,                     no_cmake=True, android_mk=True, ),
     "android-gradle": JobSpec(name="Android (Gradle)",                      os=JobOs.UbuntuLatest,  platform=SdlPlatform.Android,     artifact=None,                     no_cmake=True, android_gradle=True, ),
-    "emscripten": JobSpec(name="Emscripten",                                os=JobOs.UbuntuLatest,  platform=SdlPlatform.Emscripten,  artifact="SDL-emscripten", ),
+    "emscripten": JobSpec(name="Emscripten",                                os=JobOs.Ubuntu22_04,   platform=SdlPlatform.Emscripten,  artifact="SDL-emscripten", ),
     "haiku": JobSpec(name="Haiku",                                          os=JobOs.UbuntuLatest,  platform=SdlPlatform.Haiku,       artifact="SDL-haiku-x64",          container="ghcr.io/haiku/cross-compiler:x86_64-r1beta5", ),
     "loongarch64": JobSpec(name="LoongArch64",                              os=JobOs.UbuntuLatest,  platform=SdlPlatform.LoongArch64, artifact="SDL-loongarch64", ),
     "n3ds": JobSpec(name="Nintendo 3DS",                                    os=JobOs.UbuntuLatest,  platform=SdlPlatform.N3ds,        artifact="SDL-n3ds",               container="devkitpro/devkitarm:latest", ),