about:history - Clicking on something other than the table will clear any selections

[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).

Clicking on something other than the table will clear any selections. This had already been done for about:bookmarks.

Also, this PR updates the click area for about:bookmarks... expanding it to the whole page (instead of just the lower area). See testing notes for more info.

Fixes #5458

Auditors: @darkdh

Test Plan:

1. Launch Brave and go to about:history
2. Select a few items (from multiple tables if possible)
3. Click one of the headers to sort; notice selection is not changed.
4. Click the search box (like you want to give it focus) and notice how selection is cleared.
5. Go to about:bookmarks
6. select a few items
7. Click in the search box (like you want to give it focus). Notice how selection is cleared. Before this PR, you couldn't click the page header (ex: the search box, the page title). Clicking elsewhere did work though.

[darkdh]

lgtm