[FIX] UI Cleanup: Total balances styling changes
-Consistent on decimal points: XRP and XAU show 4 decimals point and others show 2
-Visual styling of the amount cleaned up
[FIX] Address pull-request comments

-Store ($scope.aggregateValueAsXrp / metric) in a variable to improve readability
Merge pull request #1509 from mrajvanshy/totalBalanceColor

[FIX] UI Cleanup: Total balances styling changes