fixup #14525 bug in Firefox table nav

[seanbudd]

Link to issue number:

Closes #14552

Summary of the issue:

A typo in #14070 prevents navigated to the first column in a table in Firefox.

Description of user facing changes

Use table navigation commands to move to the first column in firefox works again

Description of development approach

Fix typo

Testing strategy:

Test with STR in #14552

Known issues with pull request:

None

Change log entries:

Bug fixes

• Bug fixed when navigating to the first and last column in a table in Firefox

Code Review Checklist:

• Pull Request description:
  • description is up to date
  • change log entries
• Testing:
  • Unit tests
  • System (end to end) tests
  • Manual testing
• API is compatible with existing add-ons.
• Documentation:
  • User Documentation
  • Developer / Technical Documentation
  • Context sensitive help for GUI changes
• UX of all users considered:
  • Speech
  • Braille
  • Low Vision
  • Different web browsers
  • Localization in other languages / culture than English
• Security precautions taken.