chore(java): skip bom install instructions if there's no snippet (#494)
chore(java): skip bom install instructions if there's no snippet (#494)

* chore(java): skip bom install instructions if there's no snippet

Moving forward, new clients won't be added to the google-cloud-bom until
they are stable. Thus, we should not add the default libraries-bom
install instructions if there's no bom install snippet.

* chore: fix formatting to avoid churn
googleapis/synthtool,googleapis/synthtool,googleapis/synthtool,googleapis/synthtool,googleapis/synthtool