[mongo-cxx-driver] remove wrong includedirs

[mathbunnyru]

Thanks to @andoalon for reporting the issue and fix

Specify library name and version: lib/1.0

• I've read the guidelines for contributing.
• I've followed the PEP8 style guides for Python code in the recipes.
• I've used the latest Conan client version.
• I've tried at least one configuration locally with the
  conan-center hook activated.

[ghost]

I detected other pull requests that are modifying mongo-cxx-driver/all recipe:

• mongo-cxx-driver: use validate() for checking configuration #4057

This message is automatically generated by https://github.com/ericLemanissier/conan-center-conflicting-prs so don't hesitate to report issues/improvements there.

[conan-center-bot]

All green in build 1 (0445748e49297f68590fde1f04ff46524c6c2520)! 😊

• mongo-cxx-driver/3.6.1: Generated 132 packages. All logs here