[Detection Engine] Update toast message for adding exception

[yctercero]

Summary

Addresses #156246

Updates exception toast message to accurately reflect when it's an endpoint exception.

Checklist

• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Unit or functional tests were updated or added to match the most common scenarios
• Any UI touched in this PR is usable by keyboard only (learn more about keyboard accessibility)
• Any UI touched in this PR does not create any new axe failures (run axe in browser: FF, Chrome)
• This renders correctly on smaller devices using a responsive layout. (You can test this in your browser)
• This was checked for cross-browser compatibility

[yctercero]

/ci

[e40pud]

Thanks for the update!

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: 25a949b

Metrics [docs]

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
securitySolution	18.0MB	18.0MB	+984.0B

History

• 💛 Build #229208 was flaky 6e79d6b
• 💚 Build #229027 succeeded 6e79d6b
• 💔 Build #229002 failed 99cce9c

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

cc @yctercero

[kibanamachine]

💔 All backports failed

Status	Branch	Result
❌	8.15	Backport failed because of merge conflicts

Manual backport

To create the backport manually run:

node scripts/backport --pr 191032

Questions ?

Please refer to the Backport tool documentation