Verbum: Update Verbum comments accessibility

[agrullon95]

Fixes p4vt7e-io-p2

Proposed changes:

• Adds visible focus to WordPress.com, Facebook, and Email buttons
• Fixes email input fields visual focus (certain themes were causing a break in the UI)

Other information:

• [ ] Have you written new tests for your changes, if applicable?
• [ ] Have you checked the E2E test CI results, and verified that your changes do not break them?
• [ ] Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

Does this pull request change what data or activity we track or use?

Testing instructions:

• Sync to simple site and atomic site
• Verify Verbum Comment has accessibility visual indicators ( Logout, "X" close button, login icons, email input fields, settings toggle, comment button)