BLD: Remove FreeType from Agg backend extension

I'm not sure why this was added originally, but it seems unnecessary.
Fortunately, the waste was probably avoided by LTO.

Author: QuLogic

src/meson.build

@@ -37,7 +37,7 @@ extension_data = {
       '_backend_agg.cpp',
       '_backend_agg_wrapper.cpp',
     ),
-    'dependencies': [agg_dep, freetype_dep, pybind11_dep],
+    'dependencies': [agg_dep, pybind11_dep],
   },
   '_c_internal_utils': {
     'subdir': 'matplotlib',