Fix Ender Link Cover memory card copy/paste and required-item handling

[Lapis256]

What

Fixed the copy/paste process for Ender Link Cover settings using the Machine Memory Card.
In addition, corrected the required item determination and consumption process during pasting to ensure that requested items are handled correctly even in non-Creative mode.

Implementation Details

• Implemented getAdditionalDrops for Ender Link Cover to return internal filters as additional drops.
  • To correctly include internal filters in the required item calculation during pasting.
• Fixed required item consumption in non-Creative mode to work as expected.
  • Changed some incorrect NBT key references from literal values ("itemsToPaste") to constants (ITEMS_TO_PASTE).
  • Corrected the possession check to properly handle cases where the possessed quantity exceeds the required quantity.

Outcome

• Machine Memory Card can now copy/paste Ender Link Cover settings.
• Fixes: new feature of copying cover settings with machine memory card actually *dupes* covers #4680

How Was This Tested

Confirmed that it works as implemented in both v7.5.2 and v8.

Additionally, in v8, there was an issue where opening the Ender Link Cover's settings UI would cause a crash, so the direct cause of the crash was temporarily commented out for testing.
This comment-out was for verification purposes and is not included in this PR.

Additional Information

For reference, the direct cause of the aforementioned v8 crash is as follows:

• com.gregtechceu.gtceu.common.cover.ender.AbstractEnderLinkCover.VirtualEntryWidget#initWidgets returns null from cover.getEntry() during execution.