tests, json: Do not check for keygrip of pubkeys

* tests/json/t-keylist-secret.out.json: Do not check for keygrip
of bravo key.

--
Since GnuPG 2.2.19 the keygrip is not emitted for public keys
in a keylisting --with-secret.

As the GPGME test suite should pass with several versions
the json test cannot test this as the suite does not allow
version checks for different output.

What the intended behavior is might still be up for discussion,
always adding --with-keygip is not a good solution because
it slows down keylistings for large keyrings.

GnuPG-Bug-Id: T4820

tests/json/t-keylist-secret.out.json

@@ -113,7 +113,6 @@
                 "pubkey_algo_name":     "DSA",
                 "pubkey_algo_string":   "dsa1024",
                 "keyid":        "FE180B1DA9E3B0B2",
-                "keygrip":      "6D62909991D2331E5F4F605BC4DD738F30E6D26B",
                 "pubkey_algo":  17,
                 "length":       1024,
                 "timestamp":    920888034,
@@ -134,7 +133,6 @@
                     "pubkey_algo_name":     "ELG-E",
                     "pubkey_algo_string":   "elg1024",
                     "keyid":        "5381EA4EE29BA37F",
-                    "keygrip":      "6BBF325FADDC1109AE36CD535CA77AB9CFADD1F2",
                     "pubkey_algo":  16,
                     "length":       1024,
                     "timestamp":    920888071,