Add "n commits" link to contributors in contributors graph page (#32799)

Fixes Issue #29365 and inherit PR #29429

- I should extend the #29429 fork but the fork is not synced, so I
created another PR.
- Use `silenced` class for the link, as in #29847

---------

Co-authored-by: Ben Chang <ben_chang@htc.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

templates/repo/contributors.tmpl

@@ -1,6 +1,7 @@
 {{if .Permission.CanRead $.UnitTypeCode}}
 	<div id="repo-contributors-chart"
 		data-repo-link="{{.RepoLink}}"
+		data-repo-default-branch-name="{{.Repository.DefaultBranch}}"
 		data-locale-filter-label="{{ctx.Locale.Tr "repo.contributors.contribution_type.filter_label"}}"
 		data-locale-contribution-type-commits="{{ctx.Locale.Tr "repo.contributors.contribution_type.commits"}}"
 		data-locale-contribution-type-additions="{{ctx.Locale.Tr "repo.contributors.contribution_type.additions"}}"