fix: use correct input for strip slashes middleware (#7295)

- The router must use the escaped path in order to ensure correct functionality (at least, that is what they say). However `req.URL.Path` shouldn't be set to the escaped path, which is fixed in this patch.
- Simplify the logic and no longer try to use `rctx.RoutePath`, this is only useful if the middleware was placed after some routing parsing was done.
- Resolves forgejo/forgejo#7294
- Resolves forgejo/forgejo#7292
- Add unit test

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/7295
Reviewed-by: Earl Warren <earl-warren@noreply.codeberg.org>
Co-authored-by: Gusted <postmaster@gusted.xyz>
Co-committed-by: Gusted <postmaster@gusted.xyz>

services/context/repo.go

@@ -1058,7 +1058,7 @@ func RepoRefByType(refType RepoRefType, ignoreNotExistErr ...bool) func(*Context
 
 			if refType == RepoRefLegacy {
 				// redirect from old URL scheme to new URL scheme
-				prefix := strings.TrimPrefix(setting.AppSubURL+strings.ToLower(strings.TrimSuffix(ctx.Req.URL.Path, ctx.PathParamRaw("*"))), strings.ToLower(ctx.Repo.RepoLink))
+				prefix := strings.TrimPrefix(setting.AppSubURL+strings.ToLower(strings.TrimSuffix(ctx.Req.URL.Path, ctx.Params("*"))), strings.ToLower(ctx.Repo.RepoLink))
 
 				ctx.Redirect(path.Join(
 					ctx.Repo.RepoLink,