[SIEM] Fixes global refresh button re-enabling before map finishes loading

[spong]

Note: This is a draft PR for verifying new API functionality provided by the maps team in #49373

Summary

Fixes #49510

Introduces new useMapLayers hook for exposing a global refresh flag (isLoading) and access to the state of each layer on the map (MapLayer[]).

Hook API:

/**
 * Hook for keeping track of map layer state and when they are loading
 *
 * @returns
 * isLoading: boolean of whether or not at least one layer is currently loading
 * mapLayers: MapLayer[] current state of all layers
 * mapLayerEventHandlers: MapLayerEventHandlers to pass into mapEmbeddableFactory.createFromState() to register handlers
 */
export const useMapLayers = (): Return => { ... };

The MapLayer interface is as follows:

export interface MapLayer {
  layerId: string;
  dataId: string;
  featuresCount: number; 
  errorMessage: string;
  isLoading: boolean;
}

Checklist

Use strikethroughs to remove checklist items you don't feel are applicable to this PR.

• This was checked for cross-browser compatibility, including a check against IE11
• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Documentation was added for features that require explanation or tutorials
• Unit or functional tests were updated or added to match the most common scenarios
• This was checked for keyboard-only and screenreader accessibility

For maintainers

• This was checked for breaking API changes and was labeled appropriately
• This includes a feature addition or change that requires a release note and was labeled appropriately

[elasticmachine]

Pinging @elastic/siem (Team:SIEM)

[elasticmachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: cb0d08d

[spong]

Closing till the remainder of this work is prioritized.