When viewing a file, hide the add button (#25320)

Fix #25281
When viewing a file, hide the add button

![image](https://github.com/go-gitea/gitea/assets/89133723/839babaf-6b67-46e1-a103-677306fb8503)

![image](https://github.com/go-gitea/gitea/assets/89133723/32a8aeca-31f4-4ce1-a0fa-7656e16b66d3)

templates/repo/home.tmpl

@@ -83,7 +83,7 @@
 					<a href="{{.Repository.Link}}/find/{{.BranchNameSubURL}}" class="ui compact basic button">{{.locale.Tr "repo.find_file.go_to_file"}}</a>
 				{{end}}
 
-				{{if and .CanWriteCode .IsViewBranch (not .Repository.IsArchived)}}
+				{{if and .CanWriteCode .IsViewBranch (not .Repository.IsArchived) (not .IsViewFile)}}
 					<button class="ui dropdown basic compact jump button gt-mr-2"{{if not .Repository.CanEnableEditor}} disabled{{end}}>
 						{{.locale.Tr "repo.editor.add_file"}}
 						{{svg "octicon-triangle-down" 14 "dropdown icon"}}