Update the combineLatest code

[fireflysemantics]

https://stackoverflow.com/questions/64235967/combinelatest-refactoring-for-deprecated-resultselector-no-longer-supported

This code will fix the linting error:

    // Combine params from all of the path into a single object.
    this.params = combineLatest(
      this._route.pathFromRoot.map(route => route.params)).
      pipe(map((params:Params[])=>Object.assign({}, ...params)));