torchmetrics.retrieval.RetrievalPrecisionRecallCurve plots precision calls it False Positive Rate

## 🐛 Bug `RetrievalPrecisionRecallCurve` plots precision (x axis) and recall (y axis). However, the plot calls them False and True positive rates. While True positive rate is the same as recall, false positive rate is not the same as precision. 1. why call it FPR/TPR instead of precision and recall which are the names used on the class? 2. is the FPR label on the x axis wrong or is the computation of precision a mistake and it was meant actually to compute FPR? As a minor issue, usually, recall is on the x axis and precision on the y axis (just google precision recall curves), and would be nice if they were swapped. ### To Reproduce Precision is `true_positives / (true_positives` + false _positives)`, recall is `true_positives / real_positives`, and FPR is `false_positives / total_population`. Given this data: ``` pred = torch.tensor([1.0, .9, .8, .7, .6, .5, .4, .3, .2, .1]) target = torch.tensor([1, 1, 0, 1, 1, 0, 0, 1, 0, 0], dtype=int) ``` We should expect: | | Precision | Recall | FPR | | --- | --- | --- | --- | | 0 | 1/1 | 1/5 | 0/10 | | 1 | 2/2 | 2/5 | 0/10 | | 2 | 2/3 | 2/5 | 1/10 | | 3 | 3/4 | 3/5 | 1/10 | | 4 | 4/5 | 4/5 | 1/10 | | 5 | 4/6 | 4/5 | 2/10 | | 6 | 4/7 | 4/5 | 3/10 | | 7 | 5/8 | 5/5 | 3/10 | | 8 | 5/9 | 5/5 | 4/10 | | 9 | 5/10 | 5/5 | 5/10 | yet, we get ``` >> metric = RetrievalPrecisionRecallCurve() >> metric.update(pred, target,indexes=torch.zeros(pred.shape, dtype=int)) >> metric.compute() (tensor([1.0000, 1.0000, 0.6667, 0.7500, 0.8000, 0.6667, 0.5714, 0.6250, 0.5556, 0.5000]), tensor([0.2000, 0.4000, 0.4000, 0.6000, 0.8000, 0.8000, 0.8000, 1.0000, 1.0000, 1.0000]), tensor([ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10])) >> fig, ax = metric.plot() >> ax.set_xlim(0, 1) >> ax.set_ylim(0, 1) ``` <img width="640" height="480" alt="Image" src="https://github.com/user-attachments/assets/36de6538-ba57-4d7f-9669-26cff78bdd3c" /> <details> <summary>Environment</summary> - TorchMetrics version 1.1.2 - Python 3.11.2 - OS: GNU/Linux Debian </details>