[7.x] [Fleet] Improve default port experience in the settings UI (#102982)

[kibanamachine]

Backports the following commits to 7.x:

• [Fleet] Improve default port experience in the settings UI ([Fleet] Improve default port experience in the settings UI #102982)

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 9fc652f
• Storybooks Preview

Metrics [docs]

Module Count

Fewer modules leads to a faster build time

id	before	after	diff
fleet	473	474	+1

Public APIs missing comments

Total count of every public API that lacks a comment. Target amount is 0. Run node scripts/build_api_docs --plugin [yourplugin] --stats comments for more detailed information.

id	before	after	diff
fleet	1014	1016	+2

Async chunks

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

id	before	after	diff
fleet	690.2KB	690.6KB	+457.0B

Page load bundle

Size of the bundles that are downloaded on every page load. Target size is below 100kb

id	before	after	diff
fleet	440.6KB	441.1KB	+522.0B

Unknown metric groups

API count

id	before	after	diff
fleet	1106	1108	+2

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

cc @nchaulet