Consider limiting deploy preview link creations to the PRs that target only to the main branch

[canova]

I believe currently we put the deploy preview links on every PR. And deployment PRs get deploy preview links too, see: #6156. I tried to remove it but it gets added automatically after. it's not the end of the world, but I think it would be nicer if we don't have the links for them (since I directly use the PR message as the commit message).

cc @skylarkning

┆Issue is synchronized with this Jira Task

[skylarkning]

Will fix this! Thanks for raising this Nazim