Remove double engine reference in ossl_ec_key_dup()

Fixes #25260

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/25453)

(cherry picked from commit ffc5a29608)

crypto/ec/ec_backend.c

@@ -617,14 +617,8 @@ EC_KEY *ossl_ec_key_dup(const EC_KEY *src, int selection)
             || !EC_GROUP_copy(ret->group, src->group))
             goto err;
 
-        if (src->meth != NULL) {
-#if !defined(OPENSSL_NO_ENGINE) && !defined(FIPS_MODULE)
-            if (src->engine != NULL && ENGINE_init(src->engine) == 0)
-                goto err;
-            ret->engine = src->engine;
-#endif
+        if (src->meth != NULL)
             ret->meth = src->meth;
-        }
     }
 
     /*  copy the public key */