fix(angular:vertical-nav): navgroup togglebtn a11y

[mathisscott]

• this adds a new input to the clr-vertical-nav-group component • the new input is groupLabel/clrVerticalNavGroupLabel • it defaults to commonstrings.keys.verticalNavGroupToggle • if supplied a value, it updates the aria-label on the toggle button • previously, a custom label could not be provided to the toggle button • ...without non-trivial overrides to commonstrings

Signed-off-by: Scott Mathis smathis@vmware.com

PR Checklist

Please check if your PR fulfills the following requirements:

• [x] 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?

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

What is the current behavior?

See commit notes.

Issue Number: Tracked in a11y Jira

What is the new behavior?

See commit notes.

Does this PR introduce a breaking change?

• [ ] Yes
• [x] No -> previously there were no tests to verify the default behavior; I've added these as well as tests to verify new behavior

Other information

[mathisscott]

This fix can be backported to v12. If we want to backport it to unsupported versions, it should backport to v5 and/or v4 as well.