test(cli): add unknown mixed-audience token regression case

Signed-off-by: sergiochan <yuheng9211@qq.com>

Author: SergioChan

app/cli/internal/token/token_test.go

@@ -61,6 +61,10 @@ func TestParse(t *testing.T) {
 				TokenType: v1.Attestation_Auth_AUTH_TYPE_USER,
 			},
 		},
+		{
+			name:  "unknown audiences return nil",
+			token: "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJjcC5jaGFpbmxvb3AiLCJhdWQiOlsidW5rbm93bjEiLCJ1bmtub3duMiJdLCJleHAiOjE3MTU5MzUyNTB9.signature",
+		},
 		{
 			name:  "federated github token",
 			token: "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwczovL3Rva2VuLmFjdGlvbnMuZ2l0aHVidXNlcmNvbnRlbnQuY29tIiwiYXVkIjoiY2hhaW5sb29wIiwicmVwb3NpdG9yeSI6Im1hdGlhc2luc2F1cnJhbGRlL3Byb2plY3QiLCJzdWIiOiJyZXBvOm1hdGlhc2luc2F1cnJhbGRlL3Byb2plY3Q6cmVmOnJlZnMvaGVhZHMvbWFpbiJ9.signature",