Do not override handlers of rowAttributes when multiSelect is disabled

[darkdh]

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).

Test Plan:

fix #4695

Auditors: @bsclifton

Test Plan:

1. Go to about:preferences#search
2. Should be able to change search engine

[bsclifton]

Thanks! 😄