Deprecate support for FreeType 2.9.0

[hugovk]

We need FreeType >= 2.9.1 in some places in Pillow 10.4.0.

FreeType 2.9.1 was released on 2018-05-02.

FreeType 2.10.4 fixes a severe vulnerability: "All users should update immediately".

If deprecated in Pillow 11.0.0 (2024-10), it can be removed in Pillow 12.0.0 (2025-10).

Checking some distros from https://repology.org/project/freetype/versions:

distro	FreeType
Alpine 3.17	2.12.1
Alpine 3.18	2.12.1
Alpine 3.19	2.12.1
Alpine 3.20	2.12.1
Amazon Linux 2	2.8 / 2.4.11
Arch	2.13.3
CentOS Stream 9	2.10.4
Debian 11 Bullseye	2.10.4
Debian 12 Bookworm	2.12.1
Fedora 39	2.13.1
Fedora 40	2.13.2
Ubuntu 20.04 Focal	2.10.1
Ubuntu 22.04 Jammy	2.11.1
Ubuntu 24.04 Noble	2.13.2

Removing those distros which will be EOL before 2025-10 and sorting by FreeType version:

distro	FreeType
CentOS Stream 9	2.10.4
Debian 11 Bullseye	2.10.4
Ubuntu 22.04 Jammy	2.11.1
Alpine 3.19	2.12.1
Alpine 3.20	2.12.1
Debian 12 Bookworm	2.12.1
Ubuntu 24.04 Noble	2.13.2
Arch	2.13.3

All of these are newer than 2.9.1.

---

For reference, we deprecated support for FreeType 2.7 in Pillow 8.1.0 (issue #5075, PR #5098), and removed it in 9.0.0 (#5777).

[radarhere]

We need FreeType >= 2.9.1 in some places in Pillow 10.4.0.

For reference, this is referring to variation fonts - https://pillow.readthedocs.io/en/stable/releasenotes/6.1.0.html#variation-fonts