Conditionally ignoring a .dockerignore file on COPY
Currently there is no such way where you can provide a different .dockerignore file.
As an alternative, you can copy the node_modules to a different directory such as ./node_new_module using cp on the host OR probably integrate that cp command in your CI.
After that you can use the new ./node_new_module to copy node modules in your Dockerfile -
COPY ./node_new_modules/* node_modules/
Hope this helps or gives you a way to solve this problem.