Make ingestion more resilient by ignoring malformed and avoid field explosion

[simitt]

We want to reduce the risk of mapping conflicts. The APM solution should adopt ES features to make ingestion more resilient:

(1) Add ignore_malformed: true to the root of the mappings. See also elastic/elasticsearch#95329. Ignores fields with type conflicts instead of rejecting the whole document.
Validation Criteria: Ingesting a label foo: 42, then foo: "bar" doesn't lead to data loss

(2) Add dynamic: until_limit to avoid that field explosions lead to data loss. Relates to elastic/elasticsearch#96235.
Validation Criteria: Exceeding the field limit by creating many unique labels doesn't lead to data loss