This is a question about style and communication.
Know your audience.
If your readers are native English speakers then you can often drop such occurrences of that.
Otherwise, keeping them can help at least some readers for whom English is not their first language. In particular, it can help those whose native language(s) would use something equivalent to that.
In addition, depending on how good your translators are (from English to other languages), keeping such occurrences of that can facilitate translation.
There is a recent tendency in some documentation circles to use language that is more "conversational". Style guides that push this tend to recommend removing such occurrences of that. Similarly, style guides that promote "minimalist" text tend to recommend removing such occurrences as unnecessary noise.