[C++] Bump bundled c-ares

[raulcd]

Describe the enhancement requested

We are using a bundled c-ares version from 2021:
https://github.com/c-ares/c-ares/releases/tag/cares-1_17_2

We probably should bump to a newer version, latest is from December 2025:
https://github.com/c-ares/c-ares/releases/tag/v1.34.6

Component(s)

C++