Fix an exception caused by incorrect data handling

The prefixes in WifiEnterpriseConfig are optional, and should be treated
as such. If the prefix doesn't exist, it is possible for an
exception to be thrown (if the value size is smaller than prefix size).

Bug: 10304089

Change-Id: Id9b2bc0e371c818e35a5aa1913ee1697f167e19e
1 file changed