SSH Migration: Fix copy button border

[valterlorran]

Part of #

Proposed Changes

• Fixes the copy button border. The border should not have a border.

Before

After

Why are these changes being made?

• On production, the copy button would have an unexpected border.

Testing Instructions

Pre-merge Checklist

• Has the general commit checklist been followed? (PCYsg-hS-p2)
• Have you written new tests for your changes?
• Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• Have you checked for TypeScript, React or other console errors?
• Have you tested accessibility for your changes? Ensure the feature remains usable with various user agents (e.g., browsers), interfaces (e.g., keyboard navigation), and assistive technologies (e.g., screen readers) (PCYsg-S3g-p2).
• Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• Have we added the "[Status] String Freeze" label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?
  • For UI changes, have we tested the change in various languages (for example, ES, PT, FR, or DE)? The length of text and words vary significantly between languages.
• For changes affecting Jetpack: Have we added the "[Status] Needs Privacy Updates" label if this pull request changes what data or activity we track or use (p4TIVU-aUh-p2)?

[github-actions]

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[Copilot]

Pull Request Overview

This PR fixes a styling issue where the copy button in the SSH Migration share access step had an unexpected border on production. The fix moves the border: none declaration from a general style rule to a more specific selector that includes the is-transparent class modifier.

• Replaced the general border: none rule with a more specific &.button.is-transparent selector to ensure proper CSS specificity

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[Copilot]

The border: none declaration appears redundantly in both the new &.button.is-transparent block (lines 252-254) and the existing hover/focus/active states block (line 248). Consider consolidating these rules by moving &.button.is-transparent above the hover states and applying border: none once, or ensuring the specificity increase is intentional to override external styles.