refactor: hide git repo path details from more packages (#38601)

Remove `RepoPath` from "models/repo" package, remove `UserPath` from
"models/user" package, use `WithRepo` for more places, fine tune tests.

modules/git/repo_compare.go

@@ -15,6 +15,7 @@ import (
 	"strings"
 
 	"gitea.dev/modules/git/gitcmd"
+	"gitea.dev/modules/git/gitrepo"
 )
 
 type lineCountWriter struct {
@@ -113,7 +114,7 @@ func (repo *Repository) GetFilesChangedBetween(ctx context.Context, base, head s
 // ReadPatchCommit will check if a diff patch exists and return stats
 func (repo *Repository) ReadPatchCommit(prID int64) (commitSHA string, err error) {
 	// Migrated repositories download patches to "pulls" location
-	repoFS := GetRepoFS(repo)
+	repoFS := gitrepo.RepoLocalFS(repo)
 	loadPatch, err := repoFS.Open(fmt.Sprintf("pulls/%d.patch", prID))
 	if err != nil {
 		return "", err