fix: toggle liquidity position when toggling rates (#2117)

If field A and field B are already populated, chances are the user wants
them to remain the same and only wants to invert the price range
selector.

The conversion isn't exact, but should be preferable to the previous
behavior.

src/pages/AddLiquidity/index.tsx

@@ -606,6 +606,7 @@ export default function AddLiquidity({
                     handleRateToggle={() => {
                       onLeftRangeInput((invertPrice ? priceLower : priceUpper?.invert())?.toSignificant(6) ?? '')
                       onRightRangeInput((invertPrice ? priceUpper : priceLower?.invert())?.toSignificant(6) ?? '')
+                      onFieldAInput(formattedAmounts[Field.CURRENCY_B] ?? '')
                       history.push(
                         `/add/${currencyIdB as string}/${currencyIdA as string}${feeAmount ? '/' + feeAmount : ''}`
                       )