Suppress get_magic_quotes_gpc() deprecation notices

[SharkyKZ]

Partial Pull Request for Issue #26607.

Summary of Changes

get_magic_quotes_gpc() emits a deprecation notice on PHP 7.4:

Deprecated: Function get_magic_quotes_gpc() is deprecated

This suppresses the notice.

Testing Instructions

Code review.

Documentation Changes Required

No.

[HLeithner]

just remove this function it always returns false since php 5.4

[HLeithner]

ah forget this ;-) j3 please make a php version check suppressing error messages are a bad idea.

[SharkyKZ]

Added version check.

[euismod2336]

I have tested this item ✅ successfully on 758aa85

## in php >= 5.4 the get_magic_quotes_gpc will no longer be reached

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[AngermannMarkus]

I have tested this item ✅ successfully on 758aa85

tested with a fresh joomla 3.9.12 with an old php5.6.38, changed all three files without failures.
done a component-joomla update, also without failure.

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[HLeithner]

thx