Pull Request resolves #46865 #48336 #47581 .

• I read the Generative AI policy and my contribution is either not created with the help of AI or is compatible with the policy and GNU/GPL 2 or later.

Summary of Changes

This PR is the code created by @Ruud68 in #48336

com_joomlaupdater shares the minimum_stability variable in config.xml with com_installer minimum_stability viariable. This leads to incorrect update information for the Joomla updater

Maintainers I made this against 6.3 as it has a new function but am happy to rebase to another branch

Testing Instructions

1. in the com_joomlaupdater set in options > Minimum Stability = stable
2. in com_installer set in options > Minimum Extension Stability = development
3. in com_installer view update click [Check For Updates]
4. updates will be listed including all update with stability level 'Development' and higher
5. goto com_joomlaupdater

Actual result BEFORE applying this Pull Request

Joomla offers update to non-stable Joomla releases

Expected result AFTER applying this Pull Request

Joomla only offers updates to stable joomla releases

Link to documentations

Please select:

• Documentation link for guide.joomla.org:

• No documentation changes for guide.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed