fix: ledger transaction amount on confirm modal

[alexbarnsley]

Summary

Relates to #1562, except for transactions created for a Ledger wallet. Transactions now use a totalAmount property to display on the confirmation modal (and also for sorting). In the future, we will remove this property and look at doing it a better way, so we don't need to worry about assigning that property whenever a transaction is created.

I'll look at tests at the same time as updating to not require totalAmount.

Checklist

• Documentation (if necessary)
• Tests (if necessary)
• Ready to be merged

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (develop@35cf534). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             develop    #1572   +/-   ##
==========================================
  Coverage           ?   45.52%           
==========================================
  Files              ?      274           
  Lines              ?     6832           
  Branches           ?     1337           
==========================================
  Hits               ?     3110           
  Misses             ?     3561           
  Partials           ?      161

Impacted Files	Coverage Δ
...ransaction/TransactionForm/TransactionFormVote.vue	12.35% <ø> (ø)
...TransactionForm/TransactionFormSecondSignature.vue	15% <ø> (ø)
...actionForm/TransactionFormDelegateRegistration.vue	14.28% <ø> (ø)
...action/TransactionForm/TransactionFormTransfer.vue	32.02% <ø> (ø)

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