Symfony 6 compatibility - InputBag->get can't return an array

Problem/Motivation

This was somewhat addressed in 🐛 Symfony 6 compatibility. Fixed , but not entirely. Partially my fault because I copied the description from 🐛 [2.0.x] $request->get may no longer return array as of Symfony 6.0 (BadRequestException) Fixed which didn't explain the issue entirely. Accepting arrays as default arguments was one problem, but the underlying issue is that InputBug->get can't return arrays anymore period. My original patch had fixed both issues but what was committed had only addressed the first problem of the default value being an array.

Proposed resolution

I rerolled my original patch to 2.1.0 to fix it.