fix u256 as ref type for configurables (#5194)

## Description

This PR is part of #4794. It fix an
issue necessary to use `u256` on configurables.

## Checklist

- [x] I have linked to any relevant issues.
- [x] I have commented my code, particularly in hard-to-understand
areas.
- [x] I have updated the documentation where relevant (API docs, the
reference, and the Sway book).
- [x] I have added tests that prove my fix is effective or that my
feature works.
- [x] I have added (or requested a maintainer to add) the necessary
`Breaking*` or `New Feature` labels where relevant.
- [x] I have done my best to ensure that my PR adheres to [the Fuel Labs
Code Review
Standards](https://github.com/FuelLabs/rfcs/blob/master/text/code-standards/external-contributors.md).
- [x] I have requested a review from the relevant team or maintainers.

sway-core/src/asm_generation/fuel/fuel_asm_builder.rs

@@ -1662,7 +1662,12 @@ impl<'ir, 'eng> FuelAsmBuilder<'ir, 'eng> {
 
     // XXX reassess all the places we use this
     pub(crate) fn is_copy_type(&self, ty: &Type) -> bool {
-        ty.is_unit(self.context) || ty.is_bool(self.context) || ty.is_uint(self.context)
+        ty.is_unit(self.context)
+            || ty.is_bool(self.context)
+            || ty
+                .get_uint_width(self.context)
+                .map(|x| x < 256)
+                .unwrap_or(false)
     }
 
     fn initialise_constant(

test/src/e2e_vm_tests/test_programs/should_pass/language/u256/u256_abi/json_abi_oracle.json

@@ -1,5 +1,15 @@
 {
-  "configurables": [],
+  "configurables": [
+    {
+      "configurableType": {
+        "name": "",
+        "type": 0,
+        "typeArguments": null
+      },
+      "name": "SOME_U256",
+      "offset": 108
+    }
+  ],
   "functions": [
     {
       "attributes": null,

test/src/e2e_vm_tests/test_programs/should_pass/language/u256/u256_abi/src/main.sw

@@ -1,6 +1,10 @@
 script; 
 
+configurable {
+    SOME_U256: u256 = 0x00000000000000000000000000000000000000000000000000000001u256,
+}
+
 fn main() -> u256 {
     log(0x00000000000000000000000000000000000000000000000000000002u256);
-    0x00000000000000000000000000000000000000000000000000000001u256
+    SOME_U256
 }