Include jsonCPP headers via #include "json/json.h"

[Flamefire]

Don't use #include "include/json/json.h" which is unusual and therefore confusing
This allows to remove the header symlinking done for the system lib version

Closes #42303

Disclaimer: I've tested the system build with this which works, not 100% sure about Bazel as I'm not very familiar with it but the includes = ["include"], in the cc_library rule should mean this works.

[perfinion]

Thanks for doing this, the symlinking in jsoncpp systemlibs has annoyed me since the beginning. I made a PR some time ago ( #38327 ) but hit some test failures and was too busy to resolve the last ones.
I kicked off the tests on this one so lets see if it works better now.

Again thanks so much for taking the time to work on this!

[Flamefire]

Seems like the build worked. Seeing some strange errors on OSX related to tf::DataType* or so which looks unrelated and LLVM ERROR: Building op std.return but it isn't registered in this MLIRContext which does too but I have no idea what those errors are and if they already exist in current master

Note: I have a similar PR open but for system nasm: #42266 Would be great if you can have a look or assign someone to take care of it. Change is trivial

[mihaimaruseac]

Looks good to me. Let's import and see if anything breaks.