add cpp codegen to allow list for large files

Author: Wumpf

scripts/ci/check_large_files.py

@@ -7,6 +7,7 @@
 FILES_ALLOWED_TO_BE_LARGE = {
     "CHANGELOG.md",
     "Cargo.lock",
+    "crates/build/re_types_builder/src/codegen/cpp/mod.rs",  # TODO(andreas, #7245): This file should really be split up. Might get shorter after removing non-eager serialization path.
     "crates/build/re_types_builder/src/reflection.rs",
     "crates/store/re_dataframe/src/query.rs",
     "crates/store/re_types/src/datatypes/tensor_buffer.rs",