This bread requires 2 stages of proofing. The first stage is after mixing the dough and the second stage is before baking. Overnight proofing in the refrigerator is only required for the first stage. It actually helps the brioche develop its flavor and also helps dough to firm up which then makes it easier to shape before baking. You can, however, choose not to do the first proof overnight. Instead, you can let it proof at room temperature. Do take note that depending on your room temperature, the dough will definitely be proofing faster than in the fridge, hence you definitely cannot leave it to proof at room temperature overnight. Having said that, given that the brioche dough is very very soft, for easy handling, you would still need to refrigerate it after the first proof (if you choose not to proof overnight in the fridge). Give it a light knead after the first proof and place it in the refrigerator (cover the bowl with plastic wrap) until it is firm enough to handle. Remove from the fridge, shape dough as you wish and let it proof for the second time as usual.