fix(core): prevent race condition on programmatic scroll

[brianferry]

What I did

ScrollSpyController

1. Added a destinationTarget property for when an activeLink is set.
2. When the destinationTarget comes into view, it sets the #force flag to false and clears the destinationTarget.

There is a race condition that is causing this issue RedHat-UX/red-hat-design-system#2425 where the rh-jump-link component gets out of sync during a programmatic scroll event.

What we're doing here is instead looking to see if we've arrived at the destinationTarget and that the destinationTarget is intersected before we continue on with the onIo action.

Testing Instructions

This is a fix that will be felt upstream in RHDS

1. Build the project
2. Link the project or overwrite your scroll-spy-controller.js files in rhds-elements
3. Confirm that [bug] <rh-jump-links> Active state not consistent RedHat-UX/red-hat-design-system#2425 is not an issue for you anymore.

Notes to Reviewers

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✅ Commitlint tests passed!

More Info

{
  "valid": true,
  "errors": [],
  "warnings": [],
  "input": "fix(core): prevent race condition on programmatic scroll"
}

[bennypowers]

see also #2920

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SSR Test Run for b7e053e: Report