Unexpected removing existing groups (removing permissions for viewing podcast in admin panel)
### Viewing list of contributors in podcast causes deleting permissions
Viewing list of contributors in podcast causes deleting existing rows in `auth_groups_users` table if user has more than 2 podcasts.
Adding new podcast from panel by user (bug found on user admin@example.com) causes adding row to table `auth_groups_users` where user_id equal id of creator and group "podcast#1-admin".
If user added two podcasts, two rows will appear in table `auth_groups_users`.

On page `/podcast/2/contributors` you can see a list of contributors (here is another bug, i will describe it at the end):

but if user will refresh page, there will be only one user on a list.
After refresh, permissions are deleted and table `auth_groups_users` looks like this:

It is caused by line 154 in file: `modules/Auth/Helpers/auth_helper.php`
https://github.com/ad-aures/castopod/blob/main/modules/Auth/Helpers/auth_helper.php#L154
Function `get_podcast_group` gets groups but.... removes groups if more than one as well.
At the end, user has not permission to podcast with id 1.
### Steps to reproduce
1. Log as admin@example
2. Create two podcasts in panel
3. Go to page with a list of contributors for podcast with id 2
4. Refresh page
5. Go to podcast with id 1. -> You don't have permissions.
### Expected behavior
Viewing list of podcast's contributors doesn't delete permission from table `auth_groups_users.
### Actual behavior
Viewing list of contributors in podcast causes deleting existing rows in `auth_groups_users` table if user has more than 2 podcasts.
### Relevant logs and/or screenshots
In description.
### Context
- Castopod: branch develop
- OS: windows 11
- Browser: chrome
- Web server: Apache
### Possible fixes
Rewrite function to getting podcast's contributors. I am not sure if it doesn't occures in some another functions.
### Another bug
List of contributors for a podcast shows all rows from table auth_groups_users for a user.
It occures because of "like" clause in Modules\Auth\Models\UserModel@getPodcastContributors.
```
SELECT `dev_users`.*
FROM `dev_users`
JOIN `dev_auth_groups_users` ON `dev_users`.`id` = `dev_auth_groups_users`.`user_id`
WHERE `dev_auth_groups_users`.`group` LIKE '%podcast#1%' ESCAPE '!'
```
if podcast id equal **1** it returns also:
podcast#11-admin
podcast#12-admin
issue