fix: Replace placeholder href with actual sort-by link URL in sort-by dropdown

[nazmulhasan103]

Summary

• Sort-by dropdown <a> tags were using href="#" as a placeholder, relying only on the data-link attribute and JavaScript for navigation
• Replaced with esc_url( $value['link'] ) so the correct URL is rendered directly in the href attribute
• The data-link attribute is retained for existing JS-driven behavior (e.g. AJAX filtering)

Why this matters

• Accessibility: Screen readers and keyboard users expect functional href values on anchor elements
• SEO: Search engine crawlers follow href links, not data-* attributes — sort options were invisible to crawlers
• Graceful degradation: Sort links now work even if JavaScript fails or is disabled

Changes

templates/archive/sortby-dropdown.php

- <a href="#" class="..." data-link="<?php echo esc_attr( $value['link'] ); ?>">
+ <a href="<?php echo esc_url( $value['link'] ); ?>" class="..." data-link="<?php echo esc_attr( $value['link'] ); ?>">

Test plan

• Visit a listing archive page with the sort-by dropdown visible
• Inspect anchor elements — confirm href now contains the correct sort URL
• Click each sort option and verify the page sorts correctly
• Disable JavaScript and verify sort links still navigate to the correct URL
• Confirm no regression in JS-driven AJAX sort behavior