🐛 Stop unwrapping ulid we cannot build (#4094)

* 🐛 Stop unwrapping `ulid` we cannot build

Being able to unwrap and deconstruct data that could never be created by one arbitrary can lead to wrong shrinker from being selected and thus strange issues (edge cases but let's avoid them).

* versions

Author: dubzzz

.yarn/versions/c8458015.yml

@@ -0,0 +1,8 @@
+releases:
+  fast-check: patch
+
+declined:
+  - "@fast-check/ava"
+  - "@fast-check/jest"
+  - "@fast-check/vitest"
+  - "@fast-check/worker"

packages/fast-check/src/arbitrary/_internals/mappers/UintToBase32String.ts

@@ -114,7 +114,7 @@ export function uintToBase32StringUnmapper(value: unknown): number {
   let accumulated = 0;
   let power = 1;
   for (let index = value.length - 1; index >= 0; --index) {
-    const char = value[index].toUpperCase();
+    const char = value[index];
     const numericForChar = decodeSymbolLookupTable[char];
     if (numericForChar === undefined) {
       throw new Error('Unsupported type');