Update environment files to emsdk 3.1.73

Author: mcbarton

environment-wasm-build.yml

@@ -4,4 +4,4 @@ channels:
   - conda-forge
 dependencies:
   - cmake
-  - emscripten_emscripten-wasm32==3.1.45
+  - emscripten_emscripten-wasm32==3.1.73

environment-wasm-host.yml

@@ -3,7 +3,7 @@ channels:
   - https://repo.mamba.pm/emscripten-forge
   - https://repo.mamba.pm/conda-forge
 dependencies:
-  - emscripten-abi==3.1.45
+  - emscripten-abi==3.1.73
   - nlohmann_json
   - xeus-lite
   - xeus