Cant delete temp files from bootstrap_package.

# Bug Report

## Prerequisites

* [X] Can you reproduce the problem on TYPO3 v9.5 LTS
* [X] Can you reproduce the problem on TYPO3 v10.1 LTS
* [X] Did you [perform a cursory search](https://github.com/issues?q=is%3Aissue+user%3Abenjaminkott+repo%3Abenjaminkott%2Fbootstrap_package) to see if your bug or enhancement is already reported?

## Description

When I go to "Maintenance" --> "Remove Temporary Assets" I'm unable to delete the files/folder "/typo3temp/assets/bootstrappackage".
If I press delete I see the notice in the right top corner:

But if even after that it looks like this:

BTW I noticed this behavior since bootstrap_package v9

## Steps to Reproduce

1. Install bootstrap_package v11.0.1
2. Call the frontend
3. go to "Maintenance" --> "Remove Temporary Assets"
4. try to delete every temp Assets and see how you cant delete the ones from bootstrap_package

**Expected behavior:** Every file should be deleted

**Actual behavior:** "/typo3temp/assets/bootstrappackage" does not get deleted

Reproduce the issue through Maintenance → Remove Temporary Assets after installing bootstrap_package v11.0.1 and loading the frontend. Trace the temporary-asset deletion handling for typo3temp/assets/bootstrappackage; done means the directory and its files are removed and the maintenance view reflects that.

Written by the indexing model from the issue text.