SDL_ttf: Bump vendored harfbuzz from 2.9.1 (August 2021) to 8.1.1 (August 2023) (79848)

From 79848aac621ffe7048365e4611367e093719d884 Mon Sep 17 00:00:00 2001
From: Anonymous Maarten <[EMAIL REDACTED]>
Date: Thu, 7 Sep 2023 20:54:38 +0200
Subject: [PATCH] Bump vendored harfbuzz from 2.9.1 (August 2021) to 8.1.1
 (August 2023)

---
 external/harfbuzz | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/external/harfbuzz b/external/harfbuzz
index 43931e3e..c248ad57 160000
--- a/external/harfbuzz
+++ b/external/harfbuzz
@@ -1 +1 @@
-Subproject commit 43931e3e596c04044861770b831c8f9452e2d3b0
+Subproject commit c248ad57f98c3b069b80e6b5223c6f5ab082f15d