feat: add copy_and_replace_credentials convenience method to FlowsResource#15

saksham-nexla merged 2 commits intomainnexla-opensource/nexla-sdk-python:mainfrom

devin/1772826018-copy-replace-credentialsnexla-opensource/nexla-sdk-python:devin/1772826018-copy-replace-credentialsCopy head branch name to clipboard