Adjust Task Assignments dropdown width to make user/team name fully visible

[#1]

When you are assigning a task and begin to type a name, the list below shows the names as "Joh...Doe" for example. You then have to hover your mouse over each name to make sure you are selecting the correct one. (Same exact issue with typeahead fields as well - https://one.workfront.com/s/idea/0870z000000XhbAAAS/detail)