* [npm] upgrade to RxJS 6 (#18885)
This PR upgrades RxJS to version 6 and switches to a fork of `stream-to-observable` which includes an updated version of `any-observable` that supports RxJS 6 until https://github.com/jamestalmage/stream-to-observable/pull/10 is merged. The primary change in this version of RxJS is the movement of stream operators from `Obersable.prototype` to the `rxjs/operators` module. Some of the operators, like `catch` and `do`, have been renamed (`catchError`, and `tap`). The Obsevable factories have also been moved from static methods on the `Observable` class to named exports of the root `rxjs` module. Some of those factories have also changed slightly, like `fromEvent` which now emits arrays if the event handler is called with multiple arguments.
```js
// import the Rx namespace to get the Observable factories
import * as Rx from 'rxjs';
// import the operators as named imports
import { map, tap, switchMap } from 'rxjs/operators';
```
* [rxjs/dev-utils] fix old operator usage
* [rxjs/dev-utils] remove one more old operator
There are several cases where we want to do different things in the
optimizer based on whether we are running in the distributable version
of Kibana or running from source. Historically we have handled this by
relying on the env, but as we start to prebuild things, like TypeScript
and soon SCSS, we actually need to know if the version of Kibana running
was a result of the build process or not. To address this the src/utils
module now exports a constant: `IS_KIBANA_DISTRIBUTABLE`. This constant
will be based on the build.distributable flag being set in Kibana's
package.json, which is done automatically in the build process.
* [Monitoring/No Data] Show a "still waiting" link after 19s
* minor bug fix: spinner if _interval_ updating
* update "we tried"
* some wording changes on activating / trying to activate monitoring
* cancel the setTimeout when component gets unmounted
* more wording tweaks
* update snapshot
To get rid of angular's tooltip="..." code in the header of data cards of the data visualizer, this introduces a ml-field-title-bar directive/component.
- The directive replaces the raw template code in field_data_card.html.
- The directive itself wraps a React component which uses EUI's tooltip instead of angular's tooltip attribute.
- The previous angular template logic (about which classes and fieldnames to display) is also move to the React component
- Fixes an issue with cut off text within aggregation type dropdowns in the multi-metric and population wizard.
- Fixes the style of the dropdown to be consistent across browsers.
- Fixes 1px vertical offset between dropdown and trash-icon.
* [DOCS] 6.3 Release Notes
* [DOCS] Incorporated review comments
* [DOC] Updated note about regression because it also affects pipeline creation
* [DOCS] Minor updates to release notes
