Bundle: Update search bar with visible label for org and non-org

[AnnaGingle]

Story

As a user, I want to see the label of the search bar even after I begin typing, so that I can clearly understand the input requirements and not lose context while completing the task, in compliance with Trusted Tester SC (success criteria) 3.3.2-label-provided and WCAG SC 3.3.2: Labels or Instructions (Level A).

Additionally, as a user,
I need a consistent design pattern applied across the non-org model home and the various org model pages (domains, requests, members),
so that my experience is predictable, familiar, and easier to navigate, reducing confusion and effort as I complete tasks.

Acceptance Criteria

• Update the non-org model homepage to match this design.
• Update the org model domain page to match this design.
• Update the org model domain request page to match this design.
• Update the org model member page to match this design.
• The search bar input field and search button are tabable.
• All search bar input field's ANDI output matches the input label. For example, if the search input field's label is Search by domain name, then the ANDI/screen reader output would be Search by domain name.
• Associate the Search button with the input label using <legend> or other accessibility best practices.

Additional Context

Today the org model and non-org model search bars fail Trusted Tester SC (success criteria) 3.3.2-label-provided and WCAG SC 3.3.2:
Labels or Instructions (Level A) because the user cannot see the label after they begin typing. This issue was caught by our latest section 508 audit by the DHS Section 508 office. Providing clear and unambiguous labels and instructions (including examples of expected data formats) helps all users - but particularly those with cognitive, language, and learning disabilities - to enter information correctly.

Additionally, there are some pattern inconsistencies on the non-org model home and the various org model pages with tables (domains, requests, members). A design pattern is a reusable solution to a common problem or interaction. You can read more about patterns in Jyoti's design system presentation. Patterns help create a consistent, familiar experience for users, making interfaces easier to understand and use.
Inconsisent patterns.pdf

📚Helpful links for coding accessible labels and associating forms

• Grouping controls W3C
• Using the fieldset and legend elements GOV.UK
• ANDI Guide
• Trusted Tester docs

Issue Links

• ⏬ Caused by Design: Update table search bar so the form field label is visible #2535 and Design: Update org model table search bar so the form field label is visible #2824