refactor: Restructure Transactor::preflight to reduce boilerplate (#5592)

* Restructures `Transactor::preflight` to create several functions that will remove the need for error-prone boilerplate code in derived classes' implementations of `preflight`.

include/xrpl/protocol/Permissions.h

@@ -86,6 +86,9 @@ public:
     std::optional<TxType>
     getGranularTxType(GranularPermissionType const& gpType) const;
 
+    std::optional<std::reference_wrapper<uint256 const>> const
+    getTxFeature(TxType txType) const;
+
     bool
     isDelegatable(std::uint32_t const& permissionValue, Rules const& rules)
         const;

include/xrpl/protocol/TER.h

@@ -673,7 +673,8 @@ isTerRetry(TER x) noexcept
 inline bool
 isTesSuccess(TER x) noexcept
 {
-    return (x == tesSUCCESS);
+    // Makes use of TERSubset::operator bool()
+    return !(x);
 }
 
 inline bool