chore(deps): bump highcharts from 11.4.8 to 12.6.0

Bumps [highcharts](https://github.com/highcharts/highcharts-dist) from 11.4.8 to 12.6.0.
- [Commits](highcharts/highcharts-dist@v11.4.8...v12.6.0)

---
updated-dependencies:
- dependency-name: highcharts
  dependency-version: 12.6.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

examples/fdc3-chart-and-grid/js-chart/package.json

@@ -15,7 +15,7 @@
   "dependencies": {
     "@finos/fdc3": "^2.0.3",
     "bootstrap": "5.3.8",
-    "highcharts": "11.4.8",
+    "highcharts": "12.6.0",
     "jquery": "4.0.0",
     "tslib": "2.8.1"
   },

examples/js-chart-and-grid-messagerouter/js-chart/package.json

@@ -15,7 +15,7 @@
   "dependencies": {
     "@morgan-stanley/composeui-messaging-client": "*",
     "bootstrap": "5.3.8",
-    "highcharts": "11.4.8",
+    "highcharts": "12.6.0",
     "jquery": "4.0.0",
     "tslib": "2.8.1"
   },