Fix padding issue on preferences > home page input

[bsclifton]

• 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).

This value was used before but it ended up overriding the new styles laid down with #5442

Fixes #5680

Auditors: @jkup

Test Plan:

1. Launch Brave and open Preferences
2. Look at padding next to the text inside the "My homepage is" textbox