Remove //third_party:third_party target

Nothing depends on this target.

Change-Id: If515e74865c57a3eaed16ef9972a967600f0d176
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/110730
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/third_party/BUILD.gn b/third_party/BUILD.gn
index 07a1917..778b131 100644
--- a/third_party/BUILD.gn
+++ b/third_party/BUILD.gn
@@ -8,13 +8,6 @@
 import("//build_overrides/build.gni")
 import("../pdfium.gni")
 
-group("third_party") {
-  deps = [ ":pdfium_base" ]
-  if (pdf_bundle_freetype) {
-    deps += [ ":fx_freetype" ]
-  }
-}
-
 config("pdfium_third_party_config") {
   configs = [
     "..:pdfium_common_config",