Update emscripten build jobs to one for each platform

Author: mcbarton

.github/workflows/main.yml

@@ -191,19 +191,7 @@ jobs:
       matrix:
         include:
           - name: ubu24
-            os: ubuntu-24.04
-            emsdk_ver: "3.1.45"
-            micromamba_shell_init: bash
-          - name: ubu22
-            os: ubuntu-22.04
-            emsdk_ver: "3.1.45"
-            micromamba_shell_init: bash
-          - name: osx13-x86
-            os: macos-13
-            emsdk_ver: "3.1.45"
-            micromamba_shell_init: bash
-          - name: osx14-arm
-            os: macos-14
+            os: ubuntu-24.04-arm
             emsdk_ver: "3.1.45"
             micromamba_shell_init: bash
           - name: osx15-arm