[SPARK-38139][PYTHON][ML][TESTS] Adjust tolerance in ml.recommendatio…

…n.ALS doctest

### What changes were proposed in this pull request?

This PR reduces precision of the result in `pyspark.ml.recommendation.ALS` doctest to four decimal digits.

### Why are the changes needed?

In certain configurations, ALS consistently converges to value slightly below  `0.69291`, causing repeated test failures.

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

Existing tests, executed with configuration where this test normally fails.

Closes apache#35503 from zero323/SPARK-38139.

Authored-by: zero323 <[email protected]>
Signed-off-by: Hyukjin Kwon <[email protected]>

python/pyspark/ml/recommendation.py

@@ -320,7 +320,7 @@ class ALS(JavaEstimator, _ALSParams, JavaMLWritable, JavaMLReadable):
     >>> test = spark.createDataFrame([(0, 2), (1, 0), (2, 0)], ["user", "item"])
     >>> predictions = sorted(model.transform(test).collect(), key=lambda r: r[0])
     >>> predictions[0]
-    Row(user=0, item=2, newPrediction=0.69291...)
+    Row(user=0, item=2, newPrediction=0.6929...)
     >>> predictions[1]
     Row(user=1, item=0, newPrediction=3.47356...)
     >>> predictions[2]