No, because "partisan" would imply they work on behalf of a political party. The so-called Twitter Files themselves demonstrate that this is not true.

I'm not here to claim that people working at Twitter are unbiased. Everyone has bias. But also, there's extrinsic bias in what they're dealing with, in the sense that "both sides" aren't doing the same things. One trick is to behave egregiously and then when called out for it, claim bias.