[mod_login] - no need field cache

[alikon]

Pull Request for Issue #23147 .

Summary of Changes

removed field cache

Testing Instructions

mod_login works as before

[ghost]

I have tested this item ✅ successfully on 1a835bd

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[Quy]

I have tested this item ✅ successfully on 1a835bd

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/23152.}

[Quy]

RTC

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/23152.}