2133 small a11y updates

[jonathanbobel]

Description

Small Accessibility Improvements

Problem:
There are several small accessibility issues in the Send Message flow that need attention to improve usability and alignment with WCAG standards. These changes will ensure a more inclusive experience for all users, particularly those relying on assistive technologies.

TODO

• Acronyms like "CSV" and "TSV" are updated to use accessible alternatives, ensuring screen readers pronounce them clearly
• Add "Back to all templates" sr-only content to the breadcrumb link in the folder path
• Change the Templates breadcrumb into a nav area with an aria-label of an H1 and remove the id
• Change edit button text to Edit this template
• Adjust full "Last edited..." text to be read by a screen reader like VoiceOver
• Remove "Description Icon" alt text and just have it an empty alt text