testing/belcard: Fix linphonec's complaint about missing vcard_grammar

Status Job ID Name Coverage
  Lint
passed #167786
docker-alpine x86_64
lint

00:00:26

 
  Build
passed #167791
docker-alpine ci-build aarch64
build-aarch64

00:00:57

passed #167792
docker-alpine ci-build armv7
build-armv7

00:01:02

passed #167790
docker-alpine ci-build ppc64le
build-ppc64le

00:01:13

passed #167789
docker-alpine ci-build s390x
build-s390x

00:01:02

passed #167788
docker-alpine ci-build x86
build-x86

00:00:41

passed #167787
docker-alpine ci-build x86_64
build-x86_64

00:00:39