DiagnosticsScreen: Add padding to version number.
DiagnosticsScreen: Add padding to version number.

After OptionDivider stopped being a wide space that served as padding,
in f8f0d2ee6 "settings: Rework layout to a more standard style.",
this version number has looked crowded.  Give it some padding.

vishwesh3/zulip-mobile,vishwesh3/zulip-mobile,vishwesh3/zulip-mobile,vishwesh3/zulip-mobile