[4.2] Replace $this->_db usages in components models

[joomdonation]

Pull Request for Issue # .

Summary of Changes

This PR $this->_db in all components models by database object returned by getDatabase() method. This is not a find and replace PR, so please do careful code review before merging.

Testing Instructions

1. Use Joomla 4.2
2. Apply patch
3. Access to random pages from both frontend and backend, make sure nothing is broken
4. Please at least one careful code review.

[rdeutz]

I have tested this item ✅ successfully on 61d5341

Looks good to me

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[viocassel]

I have tested this item ✅ successfully on 61d5341

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/38025.}

[alikon]

RTC

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[roland-d]

Thanks everybody