[Docs] Remove outdated mlir-iree-dialects path when publishing website (#24611)

Remove copying of an outdated external dialects path.

Follows up on b832562e371b4562d7d2ac9ca283f777ab4b4dfe.

Signed-off-by: Artem Gindinson <gindinson@roofline.ai>

docs/website/generate_extra_files.sh

diff --git a/docs/website/generate_extra_files.sh b/docs/website/generate_extra_files.sh
index c1014c6..034e56b 100755
--- a/docs/website/generate_extra_files.sh
+++ b/docs/website/generate_extra_files.sh
@@ -39,11 +39,9 @@
 
 # Copy into a new directory before making edits, so CMake only runs when needed.
 BUILD_DIALECTS_ORIGINAL_DIR="${BUILD_DIR}/doc/Dialects"
-BUILD_EXTERNAL_DIALECTS_ORIGINAL_DIR="${BUILD_DIR}/llvm-external-projects/mlir-iree-dialects/docs/Dialects"
 BUILD_DIALECTS_PROCESSED_DIR="${BUILD_DIR}/doc/Dialects_for_website"
 mkdir -p "${BUILD_DIALECTS_PROCESSED_DIR}"
 cp -r "${BUILD_DIALECTS_ORIGINAL_DIR}/." "${BUILD_DIALECTS_PROCESSED_DIR}"
-cp -r "${BUILD_EXTERNAL_DIALECTS_ORIGINAL_DIR}/." "${BUILD_DIALECTS_PROCESSED_DIR}"
 
 BUILD_PASSES_ORIGINAL_DIR="${BUILD_DIR}/doc/Passes"
 BUILD_PASSES_PROCESSED_DIR="${BUILD_DIR}/doc/Passes_for_website"