[JENKINS-75273] Fix tabs border radius

[janfaracik]

See JENKINS-75273.

Hadn't considered multi row tabs as part of the accessibility improvements, this caused a bug where the background of the tab set was overly round. This PR fixes that and also adjusts the height ever so slightly so that it's consistent with buttons and inputs.

Before

After

Testing done

• Tabs appear as expected

Proposed changelog entries

• Fix border radius overlap when multiple lines of view names are displayed.

Proposed changelog category

/label bug,web-ui

Proposed upgrade guidelines

N/A

Submitter checklist

• The Jira issue, if it exists, is well-described.
• The changelog entries and upgrade guidelines are appropriate for the audience affected by the change (users or developers, depending on the change) and are in the imperative mood (see examples). Fill in the Proposed upgrade guidelines section only if there are breaking changes or changes that may require extra steps from users during upgrade.
• There is automated testing or an explanation as to why this change has no tests.
• New public classes, fields, and methods are annotated with @Restricted or have @since TODO Javadocs, as appropriate.
• New deprecations are annotated with @Deprecated(since = "TODO") or @Deprecated(forRemoval = true, since = "TODO"), if applicable.
• New or substantially changed JavaScript is not defined inline and does not call eval to ease future introduction of Content Security Policy (CSP) directives (see documentation).
• For dependency updates, there are links to external changelogs and, if possible, full differentials.
• For new APIs and extension points, there is a link to at least one consumer.

Desired reviewers

N/A

Before the changes are marked as ready-for-merge:

Maintainer checklist

• There are at least two (2) approvals for the pull request and no outstanding requests for change.
• Conversations in the pull request are over, or it is explicit that a reviewer is not blocking the change.
• Changelog entries in the pull request title and/or Proposed changelog entries are accurate, human-readable, and in the imperative mood.
• Proper changelog labels are set so that the changelog can be generated automatically.
• If the change needs additional upgrade steps from users, the upgrade-guide-needed label is set and there is a Proposed upgrade guidelines section in the pull request title (see example).
• If it would make sense to backport the change to LTS, a Jira issue must exist, be a Bug or Improvement, and be labeled as lts-candidate to be considered (see query).

[MarkEWaite]

Tested locally and it looks good to me. My examples looked like this at various page widths:

Narrow

Wider

[krisstern]

This makes sense

[MarkEWaite]

This PR is now ready for merge. We will merge it after approximately 24 hours if there is no negative feedback.

/label ready-for-merge

[A1exKH]

LGTM.

[uhafner]

Did someone check with the Bootstrap plugin? It seems that the borders of the tabs have been changed recently as well due to some core changes 😢 In the latest LTS everything looks ok, but not in latest weekly...

LTS:
https://ci.jenkins.io/job/Plugins/job/analysis-model/job/main/379/coverage/

498:

[uhafner]

And did someone check?

[timja]

Looks fine to me:

[janfaracik]

It's a little broken on hover - it's the Bootstrap classes conflicting with it, I'll open a PR to fix it.