ci: Support joining sdkconfig.ci files that don't end in a newline

If trailing newline is missing, the last line of that item gets merged
with the first line of the next item.

tools/find_build_apps/cmake.py

@@ -73,6 +73,8 @@ class CMakeBuildSystem(BuildSystem):
                     logging.debug("Appending {} to sdkconfig".format(sdkconfig_name))
                     with open(sdkconfig_path, "r") as f_in:
                         for line in f_in:
+                            if not line.endswith("\n"):
+                                line += "\n"
                             f_out.write(os.path.expandvars(line))
             # Also save the sdkconfig file in the build directory
             shutil.copyfile(