Reduce flakiness

[haydar-metin]

What it does

Closes eclipse-glsp/glsp#1458
Should improve flakiness.

1. Wait for the tool palette to be ready (domain specific information)
2. Use a function call for expect(...).toHaveSelected(...) to delay execution
3. Introduce graph.waitForReplacement that will wait until the provided element has been replaced with a new one.
4. Reduce clutter in locating diagram elements (see graph)
5. Updates approach for waitForCreation by using Playwright API instead of directly polling for elements by using JavaScript.

• Introduces waitForReplacement and waitForHide

6. GLSPLocator now supports accessing the root + has helper utils.

How to test

Follow-ups

Changelog

• This PR should be mentioned in the changelog

• This PR introduces a breaking change (if yes, provide more details below for the changelog and the migration guide)

• Updates constructor of BaseRoutingPoint to be object based.

• packages/glsp-playwright/src/glsp/graph/graph.wait.ts - removed, not necessary anymore.

[tortmayr]

Code looks good to me, and test seem to be way more stable now. Good job! 👍🏼