All clang docker images here are based on Debian 11 (Bullseye) but now we're moving to Debian 12 (Bookworm) primarily to use the recent versions of Cmake >= 3.20 to use CXX_STANDARD=23 for some tests ([doc](https://cmake.org/cmake/help/latest/prop_tgt/CXX_STANDARD.html))
Closes#36810
PiperOrigin-RevId: 640688681
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* nit in python interop dockerfile
* address TODO in prepare_ccache_symlinks_rc
* enable ccache for C# and ruby distribtest jobs
* use debian11 instead of bullseye consistently