The "Heur" in the ID is probably short for "heuristic", which is a term applied to intelligent scanning based on likely patterns. That means that BitDefender has detected something that it thinks *looks* like malware, but might not actually *be* malware. This might occur if the program is linked against a library that is commonly used by genuine malware, or occassionally for compressed (e.g. obfuscated) executables.
If you want a second opinion, I'd download another AV vendor's standalone scanning tool, or a tool like SpyBot Search and Destroy, (or multiple tools), run their scans on the file and see what they say. If they concur then it's probably a genuine bit of malware, if not then it's more likely BitDefender is giving a false positive and it's safe to whitelist it.
If it does come back as malware, I'd be curious to know whether this was sourced direct from DJI or not. I have had every v2.0.x release of Assistant installed (all downloaded direct from DJI) without any problems from regular scans by Windows Defender, Kaspersky AV, or SpyBot S&D on my PC, and periodic scans with Avast!'s standalone scanner have always come up clean as well.