GainAbilityTargetEffect and other must able to give EntersBattlefieldAbility for cards/permanents

[JayDi85]

from #13377

Looks like GainAbilityTargetEffect doesn't work for cards like [[What Must Be Done]] or [[Necromantic Summons]] (can't give EntersBattlefieldAbility).

Maybe there are some limitation for EntersBattlefieldAbility (e.g. it works for source only). Need research.

Code example for alternative implementation of What Must Be Done (from #13377):

        // * Release Juno -- Return target historic permanent card from your graveyard to the battlefield. It enters with two additional +1/+1 counters on it if it's a creature.
        Mode mode = new Mode(new ReturnFromGraveyardToBattlefieldTargetEffect());
        mode.addEffect(new GainAbilityTargetEffect(
                new EntersBattlefieldAbility(
                        new AddCountersSourceEffect(CounterType.P1P1.createInstance(2)),
                        WhatMustBeDoneSourceIsCreatureCondition.instance,
                        null,
                        null
                ),
                Duration.EndOfTurn,
                "It enters with two additional +1/+1 counters on it if it's a creature.",
                false
        ));
        mode.addTarget(new TargetCardInYourGraveyard(filterHistoricPermanentCard));
        this.getSpellAbility().addMode(mode.withFlavorWord("Release Juno"));

enum WhatMustBeDoneSourceIsCreatureCondition implements Condition {

    instance;

    @Override
    public boolean apply(Game game, Ability source) {
        MageObject object = game.getObject(source);
        return object != null && object.isCreature(game);
    }
}

[github-actions]

What Must Be Done - (Gatherer) (Scryfall) (EDHREC)

{3}{W}{W}
Sorcery
Choose one —
• Let the World Burn — Destroy all artifacts and creatures.
• Release Juno — Return target historic permanent card from your graveyard to the battlefield. It enters with two additional +1/+1 counters on it if it's a creature. (Artifacts, legendaries, and Sagas are historic.)

Necromantic Summons - (Gatherer) (Scryfall) (EDHREC)

{4}{B}
Sorcery
Put target creature card from a graveyard onto the battlefield under your control.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, that creature enters with two additional +1/+1 counters on it.