Roll src/third_party/fontconfig/src/ 8f169b6a9..86b48ec01 (7 commits)

Reland after revert in:
https://crrev.com/c/6799105
Architecture dependent compile error in format string is now fixed.

https://chromium.googlesource.com/external/fontconfig.git/+log/8f169b6a9c6b..86b48ec01ece

$ git log 8f169b6a9..86b48ec01 --date=short --no-merges --format='%ad %ae %s'
2025-07-29 drott [Fontations] Don't leak PatternElement values
2025-07-30 drott Architecture-dependent hex formatting of int64_t in fccache.c
2025-07-30 akira Improve a warning message
2025-07-28 wl doc: Fix two typos
2025-07-24 drott [Fontations] Remaining fix for UaF
2025-07-18 akira Add fontconfig version in FcCache
2025-07-18 akira meson: Add a missing fontconfig architecture test case

Created with:
  roll-dep src/third_party/fontconfig/src

Bug: chromium:349952802
Cq-Include-Trybots: luci.chromium.try:linux-cast-arm-rel
Change-Id: I8b58cd7bf9cd98a500f6fca8c504bda194a0e457
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6799324
Commit-Queue: Ben Wagner <bungeman@google.com>
Auto-Submit: Dominik Röttsches <drott@chromium.org>
Reviewed-by: Ben Wagner <bungeman@google.com>
Cr-Commit-Position: refs/heads/main@{#1494182}
NOKEYCHECK=True
GitOrigin-RevId: 9af749d9dfb0f4a5aaa0463bcad126973e3d5363