Only include text changes for Duo Code Review

Problem

As discussed in #538977 (comment 2505686009), we have some failures that seem to be related to binary files. It was overlooked during full file inclusion change that we're attempting to include the content of binary files. It fails with I have encountered some problems while I was reviewing. Please try again later.. Example MR with a failure duo-ui!134 (comment 2495377793)

Proposal

We should not include binary files in Duo Code Review.