Fix test_sign_verify.

Note that I created the signature text (`signature_encoded.txt`), that is used
as a text to create the `signature0` in the `test_sign_verify` by the following
steps with the `openssl` CLI on FIPS module.

```
$ OPENSSL_DIR="${HOME}/.local/openssl-3.4.0-dev-fips-debug-3c6e114959"
$ export OPENSSL_CONF="${OPENSSL_DIR}/ssl/openssl_fips.cnf"

$ echo -n "Sign me!" > data.txt
$ "${OPENSSL_DIR}/bin/openssl" dgst -sha256 -sign test/openssl/fixtures/pkey/rsa2048.pem data.txt > signature.txt
$ cat signature.txt | base64 > signature_encoded.txt
```

test/openssl/test_pkey_rsa.rb

@@ -84,19 +84,24 @@ def test_new_break
   end
 
   def test_sign_verify
-    rsa1024 = Fixtures.pkey("rsa1024")
+    # The ossl_rsa_check_key_size called in ossl_pkey_sign requires more than
+    # equal 2048 bits on protect = 1 in FIPS.
+    # https://github.com/openssl/openssl/blob/3c6e11495975a4eda4cc5886080afed6203711ac/providers/common/securitycheck.c#L68-L69
+    rsa = Fixtures.pkey("rsa2048")
     data = "Sign me!"
-    signature = rsa1024.sign("SHA256", data)
-    assert_equal true, rsa1024.verify("SHA256", signature, data)
+    signature = rsa.sign("SHA256", data)
+    assert_equal true, rsa.verify("SHA256", signature, data)
 
     signature0 = (<<~'end;').unpack1("m")
-      oLCgbprPvfhM4pjFQiDTFeWI9Sk+Og7Nh9TmIZ/xSxf2CGXQrptlwo7NQ28+
-      WA6YQo8jPH4hSuyWIM4Gz4qRYiYRkl5TDMUYob94zm8Si1HxEiS9354tzvqS
-      zS8MLW2BtNPuTubMxTItHGTnOzo9sUg0LAHVFt8kHG2NfKAw/gQ=
+      ooy49i8aeFtkDYUU0RPDsEugGiNw4lZxpbQPnIwtdftEkka945IqKZ/MY3YSw7wKsvBZeaTy8GqL
+      lSWLThsRFDV+UUS9zUBbQ9ygNIT8OjdV+tNL63ZpKGprczSnw4F05MQIpajNRud/8jiI9rf+Wysi
+      WwXecjMl2FlXlLJHY4PFQZU5TiametB4VCQRMcjLo1uf26u/yRpiGaYyqn5vxs0SqNtUDM1UL6x4
+      NHCAdqLjuFRQPjYp1vGLD3eSl4061pS8x1NVap3YGbYfGUyzZO4VfwFwf1jPdhp/OX/uZw4dGB2H
+      gSK+q1JiDFwEE6yym5tdKovL1g1NhFYHF6gkZg==
     end;
-    assert_equal true, rsa1024.verify("SHA256", signature0, data)
+    assert_equal true, rsa.verify("SHA256", signature0, data)
     signature1 = signature0.succ
-    assert_equal false, rsa1024.verify("SHA256", signature1, data)
+    assert_equal false, rsa.verify("SHA256", signature1, data)
   end
 
   def test_sign_verify_options