[5.3] Deprecate namespace property of ComponentRecord

[Fedik]

Pull Request for Issue #44737 .

Summary of Changes

The property were never initialised.
Probably left over from j4 development.

Testing Instructions

Code review

Link to documentations

Please select:

• Documentation link for docs.joomla.org:
• No documentation changes for docs.joomla.org needed
• Pull Request link for manual.joomla.org: Deprecate the namespace property of the ComponentRecord class Manual#378
• No documentation changes for manual.joomla.org needed

[laoneo]

I have tested this item ✅ successfully on 74d0212

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[HLeithner]

I have tested this item ✅ successfully on 74d0212

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/44754.}

[laoneo]

RTC

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/44754.}

[laoneo]

@Fedik can you document it as well?

[laoneo]

Needs a manual entry before it can be merged.

[laoneo]

Thanks!