fix(contextMenus/global_context_search): add error handling, improve menu title, and fix tab crash

[IshitaSingh0822]

Summary

This PR improves the global_context_search context menu extension with bug fixes,
better error handling, and a UX improvement to menu item titles.

Changes

manifest.json

• Bumped version from 1.1 to 1.2
• Improved extension description to be more user-facing
• Added "tabs" permission (required for safe tab creation)

background.js

• Added error callbacks to contextMenus.create and contextMenus.remove
  with chrome.runtime.lastError checks — previously errors were silently ignored
• Updated context menu item title to Search Google ${locale} for "%s"
  so users can see what they're searching before clicking
• Fixed a crash when tab is undefined (e.g. on chrome:// pages)
  by conditionally spreading index only when tab is available
• Minor comment typo fix: "removes" → "remove"

Testing

• Loaded extension via chrome://extensions/ in developer mode
• Verified context menu appears on text selection with correct titles
• Verified clicking a menu item opens the correct regional Google search in a new tab
• Verified no errors in the service worker DevTools console
• Passed ESLint with zero errors

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[IshitaSingh0822]

Hi maintainers, just a gentle reminder for review.
Thanks!