### Description

Dynamic mappings can greatly help the getting started experience but they currently don't apply to all types, one example is `dense_vector`.

It's been suggested to automatically map float arrays as dense vectors when there are more than 100 values, or a heuristic along these lines.
server/src/test/java/org/elasticsearch/index/mapper/DynamicMappingTests.java
b.field("one.two.three", 123);
            b.array("one.two", 1.2, 1.2, 1.2);
            b.field("one", "one");
        }));
        assertEquals(XContentHelper.stripWhitespace("""
            {
              "_doc": {
                "dynamic": "runtime",
                "runtime": {
                  "one": {
                    "type": "keyword"
                  },
                  "one.two": {
                    "type": "double"
                  },
                  "one.two.three": {
                    "type": "long"
                  },
                  "one.two.three.four": {
                    "type": "keyword"
                  }
                }
              }
            }"""), Strings.toString(doc.dynamicMappingsUpdate()));
    }
    
    public void testDottedFieldDynamicFalse() throws IOException {
        DocumentMapper defaultMapper = createDocumentMapper(
            dynamicMapping("false", b -> b.startObject("myfield").field("type", "keyword").endObject())
        );