CI: Use clang for js artifacts on Linux

We have optimizations that only work with clang (namely, our use of
FLATTEN in the bytecode interpreter).

.github/workflows/ladybird-js-artifacts.yml

@@ -50,8 +50,8 @@ jobs:
       - name: Create build directory Ubuntu
         run: |
           cmake --preset Distribution_CI \
-            -DCMAKE_C_COMPILER=gcc-13 \
-            -DCMAKE_CXX_COMPILER=g++-13 \
+            -DCMAKE_C_COMPILER=clang-18 \
+            -DCMAKE_CXX_COMPILER=clang++-18 \
             -DENABLE_GUI_TARGETS=OFF
         if: ${{ matrix.os_name == 'Linux' }}