[F4:TF2] Transaction List View

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As a user, when I am in the expense detail view, I want to see a list of all of the transactions associated with that view (if there are any) so that I can see which transactions affect my current expense balance.

**User Expectations:**

- See the list of transactions for the selected expense.
- Transactions that add money to the expense should show as a positive value.
- Transactions that subtract money from the expense should show as a negative value.

**Developer Dependencies:**
- Dependent on completion of issue #104

Start in the expense detail view and review issue #104, which this work depends on. Implement a transaction list for the selected expense, showing no list when there are no transactions and displaying additions as positive values and subtractions as negative values.

Written by the indexing model from the issue text.