Revert "contrib: enable rav1e for wasm32-emscripten"

This reverts commit 6db5fb2b.

The wasm script currently builds with --disable-sout. So rav1e (AV1 encoder) will never be used.

Once/if disable-sout is removed then it will be picked automatically.

See discussion in !3755 (comment 434796)

extras/package/wasm-emscripten/build.sh

@@ -146,7 +146,7 @@ diagnostic "vlc contribs: bootstrap"
             --disable-speexdsp --disable-taglib --disable-zvbi \
             --disable-rnnoise --disable-libaribcaption \
             --disable-ogg --disable-vorbis --disable-kate --disable-flac \
-            --host=wasm32-unknown-emscripten --enable-rav1e
+            --host=wasm32-unknown-emscripten
 
 diagnostic "vlc contribs: make"
 if [ "$VLC_USE_PREBUILT_CONTRIBS" -ne "0" ]; then