[7.9] [maps] fix fit to bounds for ES document layers with joins (#73985

) (#74041)

* [maps] fix fit to bounds for ES document layers with joins (#73985)

# Conflicts:
#	x-pack/plugins/maps/public/classes/layers/vector_layer/vector_layer.js
#	x-pack/test/functional/apps/maps/auto_fit_to_bounds.js

* rename hasJoins to _hasJoins

x-pack/plugins/maps/public/classes/layers/vector_layer/vector_layer.js

@@ -158,7 +158,7 @@ export class VectorLayer extends AbstractLayer {
 
   async getBounds({ startLoading, stopLoading, registerCancelCallback, dataFilters }) {
     const isStaticLayer = !this.getSource().isBoundsAware();
-    if (isStaticLayer) {
+    if (isStaticLayer || this._hasJoins()) {
       return getFeatureCollectionBounds(this._getSourceFeatureCollection(), this._hasJoins());
     }