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/InternalGeoCentroidTests.java
Long.MAX_VALUE,
            Collections.emptyMap()
        );
        InternalGeoCentroid reducedGeoCentroid = maxValueGeoCentroid.reduce(Collections.singletonList(maxValueGeoCentroid), null);
        assertThat(reducedGeoCentroid.count(), equalTo(Long.MAX_VALUE));
    }
    @Override
    protected void assertFromXContent(InternalGeoCentroid aggregation, ParsedAggregation parsedAggregation) {
        assertTrue(parsedAggregation instanceof ParsedGeoCentroid);
        ParsedGeoCentroid parsed = (ParsedGeoCentroid) parsedAggregation;
        assertEquals(aggregation.centroid(), parsed.centroid());
        assertEquals(aggregation.count(), parsed.count());
    }
    @Override
    protected InternalGeoCentroid mutateInstance(InternalGeoCentroid instance) {
        String name = instance.getName();
        GeoPoint centroid = instance.centroid();
        long count = instance.count();
        Map<String, Object> metadata = instance.getMetadata();
        switch (between(0, 2)) {
            case 0:
                name += randomAlphaOfLength(5);
                break;
            case 1:
                count += between(1, 100);
                if (centroid == null) {
                    
                    
                    centroid = new GeoPoint(randomDoubleBetween(-90, 90, false), randomDoubleBetween(-180, 180, false));
                }