Refactor: aura's target legality check on attachment must be reworked (303.4g)

Unfinished implementation from https://github.com/magefree/mage/pull/12098#issuecomment-2252622155 uses bad and limited workaround with data modification. Search bad code by `copy().withNotTarget(true)`

It must be reworked to use normal code and check like isStilLegal or like that -- without target modification and with full and mutiple targets support.

Also can be related 702.5. and #9583

Search for `copy().withNotTarget(true)` and review the unfinished implementation discussed in pull request #12098. Compare the attachment legality logic with checks such as `isStilLegal`, along with rule 702.5 and issue #9583. Done means the check uses normal code without target modification and supports full, multiple-target legality.

Written by the indexing model from the issue text.