refactor: migrate current-account callers from NewMoneyFromInstrument to NewAmountFromInstrument (#2118)

Remove the two test-only callers of the deprecated NewMoneyFromInstrument function. The
ValidCurrency and NonCurrencyDimension test cases are superseded by the existing
TestNewAmountFromInstrument_AllDimensions suite which covers all dimension types.

Strengthen the deprecation notice on NewMoneyFromInstrument to document that all callers
have been migrated and the function is a candidate for removal.

Co-authored-by: Ben Coombs <bjcoombs@users.noreply.github.com>

Author: bjcoombs

services/current-account/domain/quantity.go

@@ -89,7 +89,9 @@ var NewMoney = func(currencyCode string, amountMinorUnits int64) (Amount, error)
 // NewMoneyFromInstrument creates an Amount from persisted instrument_code + dimension and minor-unit amount.
 // Returns ErrInvalidCurrency if dimension is not "CURRENCY".
 //
-// Deprecated: Use NewAmountFromInstrument for new code which supports all dimensions.
+// Deprecated: Use NewAmountFromInstrument instead. NewMoneyFromInstrument rejects non-CURRENCY
+// dimensions (e.g. ENERGY, CARBON, COMPUTE) and hard-codes precision=2. All callers have been
+// migrated to NewAmountFromInstrument. This function will be removed in a future release.
 var NewMoneyFromInstrument = func(instrumentCode, dimension string, amountMinorUnits int64) (Amount, error) {
 	if strings.ToUpper(dimension) != quantity.DimensionCurrency {
 		return Amount{}, ErrInvalidCurrency

services/current-account/domain/quantity_test.go

@@ -295,18 +295,6 @@ func TestNewAmountFromInstrument_InvalidDimension_ReturnsError(t *testing.T) {
 	// (not ErrInstrumentMismatch which is for arithmetic on different instruments)
 }
 
-func TestNewMoneyFromInstrument_ValidCurrency(t *testing.T) {
-	m, err := NewMoneyFromInstrument("GBP", "CURRENCY", 5000)
-	assert.NoError(t, err)
-	assert.Equal(t, "GBP", m.InstrumentCode())
-	assert.Equal(t, int64(5000), toMinorUnits(m))
-}
-
-func TestNewMoneyFromInstrument_NonCurrencyDimension(t *testing.T) {
-	_, err := NewMoneyFromInstrument("KWH", "ENERGY", 100)
-	assert.ErrorIs(t, err, ErrInvalidCurrency)
-}
-
 func TestZeroMoney_ValidCurrency(t *testing.T) {
 	m, err := ZeroMoney("GBP")
 	assert.NoError(t, err)