[Maps][ML] Typical to actual connector lines in AnomalyLayer have dot halfway

[thomasneirynck]

Kibana version:

main/8.7

Describe the bug:

The typical to actual line in the AnomalyLayer have a dot halfway.

Steps to reproduce:

1. create lon-lat anomaly detection job in ML
2. in Maps, add anomaly-layer for that type.
3. Open layer-settings. Change type to typical to actual in the Anomalies section.

Expected behavior:

The dot is not there.

Any additional context:

This was raised first here #147797 (comment)

This is likely a regression. The regression may not have been caused because of any changes in the AnomalySource. Instead, changes in Maps may have revealed some incomplete implementation in AnomalySource (?).

e.g. the placement of that point is where the label should be placed. So the point-location for the dot is likely created by Maps, not by ML.

[elasticmachine]

Pinging @elastic/kibana-presentation (Team:Presentation)

[elasticmachine]

Pinging @elastic/ml-ui (:ml)

[nreese]

I have isolated the problem. The problem occurs because the layer is of type GEOJSON_VECTOR but AnomalySource implements IVectorSource.isMvt which returns true. The mismatch between geojson layer and mvt source is causing the problems.

Short term fix, ML layers with AnomalySource should use layer type MVT_VECTOR.

Longer term, Maps should not store and use state information in 2 locations. GEOJSON_VECTOR and MVT_VECTOR should be consolidated into a single layer type VECTOR and then layer implementation should be selected based on vectorSource.isMvt method.

[nreese]

Opened #149270 for short term fix