lib: cpp: remove deprecated Kconfigs

These Kconfigs should have been deprecated for more than 2
releases, remove them:

- `CONFIG_CPP_MAIN`
- `CONFIG_CPLUSPLUS`
- `CONFIG_LIB_CPLUSPLUS`
- `CONFIG_EXCEPTIONS`
- `CONFIG_RTTI`

Signed-off-by: Yong Cong Sin <ycsin@meta.com>

tests/ztest/zexpect/CMakeLists.txt

@@ -10,7 +10,7 @@ else()
   find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
   project(base)
 
-  if(CONFIG_CPLUSPLUS)
+  if(CONFIG_CPP)
     message(STATUS "adding main.cpp")
     target_sources(app PRIVATE src/main.cpp)
   else()

tests/ztest/zexpect/testcase.yaml

@@ -12,6 +12,6 @@ tests:
       - native_sim
   testing.ztest.expect_cpp:
     extra_configs:
-      - CONFIG_CPLUSPLUS=y
+      - CONFIG_CPP=y
   testing.ztest.expect.unit:
     type: unit