Remove unnecessary forced -fno-exceptions for web builds

The SCons build doesn't do this, so neither should CMake
Excpetions are already handled by DISABLE_EXCEPTIONS option

(cherry picked from commit 43690cb60b)

cmake/web.cmake

@@ -23,7 +23,6 @@ function(web_generate)
         PUBLIC #
             -sSIDE_MODULE
             -sSUPPORT_LONGJMP=wasm
-            -fno-exceptions
             $<${THREADS_ENABLED}:-sUSE_PTHREADS=1>
     )