Copilot getIncludes doesn't return includes from other workspace folders

[sean-mcmanus]

Create 2 workspace folders and add them to a workspace. Add a test1.cpp to one folder with #include "test2.h" and a test2.h to the other workspace folder, and add a ${workspaceFolder}/../folder2 to the includePath property in the c_cpp_properties.json in folder1.

Bug: The getIncludes (for Copilot chat) doesn't return the include for the other workspace folder.