mbedtls: Update to upstream 3.6.2

[akien-mga]

Security fix: https://github.com/Mbed-TLS/mbedtls/releases/tag/mbedtls-3.6.2

For 4.2 and earlier, we should look if there's an update to mbedtls 2.28.x LTS.

Edit: This specific security issue doesn't seem to affect 2.28.x:

The vulnerability is present in Mbed TLS 3.5.x, Mbed TLS 3.6.0 and Mbed TLS 3.6.1. Earlier versions had a different implementation of the problematic cases and are not affected.

But there is a 2.28.9 we missed in August that we should update 4.2 and earlier branches to.

[Faless]

LGTM

[Repiteo]

Thanks!