[BUG] Make Probability metric not trigger Loglikehood requests twice when used alongside Accuracy Metrics

[hynky1999]

Describe the bug

When Probability metric is used alongside Accuracy metric, we evaluate 2xN_SAMPLES requests. We don't need to do this as both use the same logprobabilities for evaluation.

To Reproduce

Use this as custom tasks

from lighteval.metrics.metrics import Metrics
from lighteval.tasks.lighteval_task import LightevalTaskConfig
from lighteval.tasks.default_prompts import LETTER_INDICES
from lighteval.metrics.normalizations import LogProbCharNorm, LogProbPMINorm, LogProbTokenNorm
from lighteval.tasks.templates.utils.formulation import CFFormulation, HybridFormulation, MCFFormulation
from lighteval.tasks.templates.multichoice import get_mcq_prompt_function
from lighteval.tasks.templates.hellaswag import get_hellaswag_prompt_function
from lighteval.tasks.templates.qa import get_qa_prompt_function
from lighteval.metrics.dynamic_metrics import loglikelihood_acc_metric, probability_metric
from lighteval.tasks.multilingual.utils.task_utils import get_metrics_for_formulation
from lighteval.tasks.multilingual.tasks import xcsqa_tasks
from lighteval.utils.language import Language
from lighteval.metrics.metrics import Metrics

hellaswag_task = [
    LightevalTaskConfig(
        name=f"hellaswag_cf",
        suite=["lighteval"],
        prompt_function=get_hellaswag_prompt_function(
            language=Language.ENGLISH,
            adapter=lambda line: {
                # We don't use activity_label as they are not available
                "ctx_a": line["ctx_a"],
                "ctx_b": line["ctx_b"],
                "continuations": line["endings"],
                "gold_idx": int(line["label"]),
            },
            formulation=CFFormulation(),
        ),
        hf_repo="Rowan/hellaswag",
        hf_subset="default",
        evaluation_splits=["validation"],
        hf_avail_splits=["train", "validation"],
        metric=get_metrics_for_formulation(
            CFFormulation(),
            [
                loglikelihood_acc_metric(normalization=LogProbTokenNorm()),
                probability_metric(normalization=None),
            ],
        ),
    )
]

Expected behavior

Only N_SAMPLES loglikelihood requests are called.

Version info

commit: 1607dc1