[settings] Fix regression (setting reuse)

[enen92]

Description

This PR fixes the other known regression in addon settings introduced with the settings rework. In v17 we were able to use settings with the same id in different categories and the respective controls would stay in sync. In v18 this only works on a per-category basis. The issue is reported by @ronie here: https://forum.kodi.tv/showthread.php?tid=326633&pid=2687641#pid2687641

This PR moves the settingsId variable prior to the category detection so categories can refer to the same set.

Motivation and Context

Fix regressions for addons in Leia.

How Has This Been Tested?

Compiled and tested with the example posted in the linked thread.

Screenshots (if appropriate):

Types of change

• Bug fix (non-breaking change which fixes an issue)
• Clean up (non-breaking change which removes non-working, unmaintained functionality)
• Improvement (non-breaking change which improves existing functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that will cause existing functionality to change)
• Cosmetic change (non-breaking change that doesn't touch code)
• None of the above (please explain below)

Checklist:

• My code follows the Code Guidelines of this project
• My change requires a change to the documentation, either Doxygen or wiki
• I have updated the documentation accordingly
• I have read the Contributing document
• I have added tests to cover my change
• All new and existing tests passed

[Montellese]

The changes look sane but I don't remember all the details of the refactor.

[DaveTBlake]

@enen92 since @Montellese says it looks sane then I suggest you merge this, at least it is one step to getting addon settings working in the new settings format

[enen92]

Thanks @DaveTBlake, merging