Restore history button and hide add button when unable to add (#20718)

Fix two regressions from #20602:

- Restore the 'History' button that was previously unable to render
  because it's show condition was never hit
- Hide the 'Add File' button when there would be no items in the
  dropdown.

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

templates/repo/home.tmpl

@@ -73,6 +73,7 @@
 						</a>
 					{{end}}
 					<a href="{{.Repository.Link}}/find/{{.BranchNameSubURL}}" class="ui compact basic button tooltip" data-content="{{.locale.Tr "repo.find_file.go_to_file"}}">{{svg "octicon-file-moved" 15}}</a>
+					{{if or .CanAddFile .CanUploadFile}}
 						<button class="ui basic small compact dropdown jump icon button mr-2">
 							<span class="text">{{.locale.Tr "repo.editor.add_file"}}</span>
 							<div class="menu">
@@ -93,14 +94,10 @@
 										</a>
 									{{end}}
 								{{end}}
-							{{if and (ne $n 0) (not .IsViewFile) (not .IsBlame) }}
-								<a class="item"href="{{.RepoLink}}/commits/{{.BranchNameSubURL}}/{{.TreePath | PathEscapeSegments}}">
-									{{.locale.Tr "repo.file_history"}}
-								</a>
-							{{end}}
 							</div>
 							{{svg "octicon-triangle-down" 14 "dropdown icon"}}
 						</button>
+					{{end}}
 				{{else}}
 					<span class="ui breadcrumb repo-path"><a class="section" href="{{.RepoLink}}/src/{{.BranchNameSubURL}}" title="{{.Repository.Name}}">{{EllipsisString .Repository.Name 30}}</a>{{range $i, $v := .TreeNames}}<span class="divider">/</span>{{if eq $i $l}}<span class="active section" title="{{$v}}">{{EllipsisString $v 30}}</span>{{else}}{{ $p := index $.Paths $i}}<span class="section"><a href="{{$.BranchLink}}/{{PathEscapeSegments $p}}" title="{{$v}}">{{EllipsisString $v 30}}</a></span>{{end}}{{end}}</span>
 				{{end}}
@@ -133,6 +130,11 @@
 					{{end}}
 					</div>
 				{{end}}
+				{{if and (ne $n 0) (not .IsViewFile) (not .IsBlame) }}
+					<a class="ui button" href="{{.RepoLink}}/commits/{{.BranchNameSubURL}}/{{.TreePath | PathEscapeSegments}}">
+						{{svg "octicon-history" 16 "mr-3"}}{{.locale.Tr "repo.file_history"}}
+					</a>
+				{{end}}
 			</div>
 		</div>
 		{{if .IsViewFile}}