Revert "Make //third_party/fontconfig explicitly depend on //third_party:freetype_harfbuzz."

This reverts commit 0baa5bdf.

Reason for revert: is not needed after https://chromium-review.googlesource.com/c/chromium/src/+/1362457

Original change's description:
> Make //third_party/fontconfig explicitly depend on //third_party:freetype_harfbuzz.
> 
> Bug: 911836
> Change-Id: Ia76687b3cb8d329792e5ef0310faee93d05344f2
> Reviewed-on: https://chromium-review.googlesource.com/c/1361725
> Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
> Commit-Queue: Max Moroz <mmoroz@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#613792}

TBR=bungeman@chromium.org,mmoroz@chromium.org,thomasanderson@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 911836
Change-Id: Ibc4c88faadd5c1e603fc0f26ce956c282909798e
Reviewed-on: https://chromium-review.googlesource.com/c/1365083Reviewed-by: Max Moroz <mmoroz@chromium.org>
Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#614534}

third_party/fontconfig/BUILD.gn

@@ -76,9 +76,6 @@ if (use_bundled_fontconfig) {
     configs += [ "//build/config/compiler:no_chromium_code" ]
 
     public_configs = [ ":fontconfig_config" ]
-    public_deps = [
-      "//third_party:freetype_harfbuzz",
-    ]
 
     if (is_clang) {
       cflags = [