Use router param for filepath in GetRawFile (#19499)

* Use router param for filepath

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Move TreePath back into RepoRefForAPI

Signed-off-by: jolheiser <john.olheiser@gmail.com>

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: 6543 <6543@obermui.de>

modules/context/api.go

@@ -362,6 +362,7 @@ func RepoRefForAPI(next http.Handler) http.Handler {
 				return
 			}
 			ctx.Repo.Commit = commit
+			ctx.Repo.TreePath = ctx.Params("*")
 			return
 		}