Removed duplicate build setting

`GCC_WARN_UNINITIALIZED_AUTOS = YES` only needs to be declared once, unless it's one of those mythical beasts where it should really be `GCC_WARN_UNINITIALIZED_AUTOS = YES_FOR_REAL_THIS_TIME`

For verification, both of the duplicates are at:
https://github.com/jspahrsummers/xcconfigs/blob/4a00c43bc2b9bb5d6dc57f315bb822f487e5387b/Base/Common.xcconfig#L60
https://github.com/jspahrsummers/xcconfigs/blob/4a00c43bc2b9bb5d6dc57f315bb822f487e5387b/Base/Common.xcconfig#L144

:two_hearts: