manifest: mbedtls: update to 3.6.4

Pull in Mbed TLS 3.6.4, updated from 3.6.3.

More details regarding the Mbed TLS 3.6.4 release at:
https://github.com/Mbed-TLS/mbedtls/releases/tag/mbedtls-3.6.4



Signed-off-by: Flavio Ceolin <flavio@hubblenetwork.com>