Fix Frax Test inheritance for child repo

Fix relative vs strict import for use in inheriting repo

src/FraxTest.sol

@@ -3,7 +3,7 @@ pragma solidity >=0.8.0;
 
 import { console2 as console, StdAssertions, StdChains, StdCheats, stdError, StdInvariant, stdJson, stdMath, StdStorage, stdStorage, StdUtils, Vm, StdStyle, TestBase, DSTest, Test } from "forge-std/Test.sol";
 import { VmHelper } from "./VmHelper.sol";
-import { Strings } from "src/StringsHelper.sol";
+import { Strings } from "./StringsHelper.sol";
 
 abstract contract FraxTest is VmHelper, Test {
     uint256[] internal snapShotIds;