minor symfony#59203 [JsonEncoder] Reuse decodeString in NativeDecoder (alamirault)

This PR was merged into the 7.3 branch.

Discussion
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[JsonEncoder] Reuse decodeString in NativeDecoder

| Q             | A
| ------------- | ---
| Branch?       | 7.3
| Bug fix?      | no
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Issues        | Fix #... <!-- prefix each issue number with "Fix #", no need to create an issue if none exists, explain below instead -->
| License       | MIT

Commits
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0e83e1e [JsonEncoder] Use reuse decodeString in NativeDecoder

Author: chalasr

src/Symfony/Component/JsonEncoder/Decode/NativeDecoder.php

@@ -40,10 +40,6 @@ public static function decodeStream($stream, int $offset = 0, ?int $length = nul
             $json = $stream->read($length);
         }
 
-        try {
-            return json_decode($json, associative: true, flags: \JSON_THROW_ON_ERROR);
-        } catch (\JsonException $e) {
-            throw new UnexpectedValueException('JSON is not valid: '.$e->getMessage());
-        }
+        return self::decodeString($json);
     }
 }