fix(stack-view): increase size of change notification mark (#1207)

## PR Checklist

Please check if your PR fulfills the following requirements:

- [ ] Tests for the changes have been added (for bug fixes / features)
- [ ] Docs have been added / updated (for bug fixes / features)
- [ ] If applicable, have a visual design approval

## PR Type

What kind of change does this PR introduce?

<!-- Please check the one that applies to this PR using "x". -->

- [x] Bugfix
- [ ] Feature
- [ ] Code style update (formatting, local variables)
- [ ] Refactoring (no functional changes, no api changes)
- [ ] Build related changes
- [ ] CI related changes
- [ ] Documentation content changes
- [ ] Other... Please describe:

## What is the current behavior?

Notification icon size is 8x8 px.

Issue Number: cde-1644

## What is the new behavior?

Notification icon size is 12x12 px.

## Does this PR introduce a breaking change?

- [ ] Yes
- [x] No

<!-- If this PR contains a breaking change, please describe the impact
and migration path for existing applications below. -->

## Other information

---------

Co-authored-by: GitHub <[email protected]>

projects/angular/src/data/stack-view/_stack-view.clarity.scss

@@ -77,8 +77,8 @@
       content: ' ';
       position: absolute;
       @include mixins.equilateral(0);
-      border-top: tokens.$cds-global-space-5 solid stack-view-variables.$clr-stack-block-changed-border-top-color;
-      border-right: tokens.$cds-global-space-5 solid transparent;
+      border-top: tokens.$cds-global-space-6 solid stack-view-variables.$clr-stack-block-changed-border-top-color;
+      border-right: tokens.$cds-global-space-6 solid transparent;
     }
 
     .stack-block-caret {