The following aggregation tests all contain switch statements with branches that will never execute. The tests use a `between(x, y)` switch expression, but there are `case` values that are outside the randomised range. We need to fix these before #88739 can be merged. By "fix", I mean either remove the spurious cases, or if we actually want them, then extend the randomized range.

   * InternalAutoDateHistogramTests
   * InternalAvgTests
   * InternalDerivativeTests
   * InternalGeoCentroidTests
   * InternalWeightedAvgTests
   * SignificantLongTermsTests
   * SignificantStringTermsTests
server/src/test/java/org/elasticsearch/search/aggregations/metrics/InternalAvgTests.java
@Override
    protected InternalAvg createTestInstance(String name, Map<String, Object> metadata) {
        DocValueFormat formatter = randomNumericDocValueFormat();
        long count = frequently() ? randomNonNegativeLong() % 100000 : 0;
        return new InternalAvg(name, randomDoubleBetween(0, 100000, true), count, formatter, metadata);
    }
    @Override
    protected void assertReduced(InternalAvg reduced, List<InternalAvg> inputs) {
        double sum = 0;
        long counts = 0;
        for (InternalAvg in : inputs) {
            sum += in.getSum();
            counts += in.getCount();
        }
        assertEquals(counts, reduced.getCount());
        assertEquals(sum, reduced.getSum(), 0.0000001);
        assertEquals(sum / counts, reduced.value(), 0.0000001);
    }
    @Override