fix(earn): use statsig dynamic config for app fee (#6062)

### Description

Uses the Statsig dynamic config to determine if swap fees should be
waived.

### Test plan

- [x] Unit tests updated
- [x] Tested locally with current backend

### Related issues

Part of ACT-1379

### Backwards compatibility

Yes

### Network scalability

N/A

src/earn/prepareTransactions.test.ts

@@ -5,6 +5,8 @@ import {
 } from 'src/earn/prepareTransactions'
 import { isGasSubsidizedForNetwork } from 'src/earn/utils'
 import { triggerShortcutRequest } from 'src/positions/saga'
+import { getDynamicConfigParams } from 'src/statsig'
+import { StatsigDynamicConfigs } from 'src/statsig/types'
 import { TokenBalance } from 'src/tokens/slice'
 import { NetworkId } from 'src/transactions/types'
 import { prepareTransactions } from 'src/viem/prepareTransactions'
@@ -57,6 +59,14 @@ describe('prepareTransactions', () => {
       feeCurrency: mockFeeCurrency,
     }))
     jest.mocked(isGasSubsidizedForNetwork).mockReturnValue(false)
+    jest.mocked(getDynamicConfigParams).mockImplementation(({ configName }) => {
+      if (configName === StatsigDynamicConfigs.SWAP_CONFIG) {
+        return {
+          enableAppFee: true,
+        }
+      }
+      return {} as any
+    })
   })
 
   describe('prepareDepositTransactions', () => {
@@ -198,6 +208,7 @@ describe('prepareTransactions', () => {
         expect(triggerShortcutRequest).toHaveBeenCalledWith('https://hooks.api', {
           address: '0x1234',
           appId: mockEarnPositions[0].appId,
+          enableSwapFee: true,
           networkId: mockEarnPositions[0].networkId,
           shortcutId: 'swap-deposit',
           swapFromToken: {

src/earn/prepareTransactions.ts

@@ -7,6 +7,9 @@ import { triggerShortcutRequest } from 'src/positions/saga'
 import { RawShortcutTransaction } from 'src/positions/slice'
 import { rawShortcutTransactionsToTransactionRequests } from 'src/positions/transactions'
 import { EarnPosition } from 'src/positions/types'
+import { getDynamicConfigParams } from 'src/statsig'
+import { DynamicConfigs } from 'src/statsig/constants'
+import { StatsigDynamicConfigs } from 'src/statsig/types'
 import { SwapTransaction } from 'src/swap/types'
 import { TokenBalance } from 'src/tokens/slice'
 import Logger from 'src/utils/Logger'
@@ -33,6 +36,9 @@ export async function prepareDepositTransactions({
   hooksApiUrl: string
   shortcutId: EarnDepositMode
 }) {
+  const enableSwapFee = getDynamicConfigParams(
+    DynamicConfigs[StatsigDynamicConfigs.SWAP_CONFIG]
+  ).enableAppFee
   const args =
     shortcutId === 'deposit'
       ? {
@@ -51,6 +57,7 @@ export async function prepareDepositTransactions({
             address: token.address,
             isNative: token.isNative ?? false,
           },
+          enableSwapFee,
         }
 
   const {