Fixed context menu subitems display when the window is small

[ghost]

Original title: Y position of context menu subitems is wrong when overflowed
Bookmark submenu expansion bug

Test plan

#7661 (comment)

1. Launch Brave and minimize your browser window as far as possible
2. Click the kabob menu
3. Scroll the menu with your mouse and keyboard to ~1/3 from the bottom
4. Select "Bookmark" submenu
5. Items should line up. It should NOT look like this (image courtesy of @luixxiul):
   

Original issue description

Hello Dev team,

today i saw the following bug happening on the bookmark toolbar menu.
When i open a submenu it will appear way up , you can see that in the following screen shot:

OS : windows 7 64bit SP1
Brave : 0.9.3

[ghost]

Just to add , this does not happen on all existing submenus , it will happen in a random amount , some of them may work correctly but the others no.

[luixxiul]

Still reproducible?

[ghost]

@luixxiul yep still reproducible , just updated to 0.10.0 64 bit

[luixxiul]

I'm trying but cannot reproduce it.. Would you please tell me how many bookmarks are in the left pulldown?

[ghost]

@luixxiul i have in that folder 191 items , 29 of them are folders and they are in the middle way of the folder.
i have imported these bookmarks from firefox so maybe you can do it that way.

[ghost]

@luixxiul i can give you a remote access to my machine incase you want to see it for yourself , let me know if thats required.

[luixxiul]

I'll try by myself and will ask you if I need it, thanks.

[ghost]

@luixxiul sure

[luixxiul]

I think I can reproduce the error consistently.

STR:

1. Minimize your browser window as far as possible
2. Click the kabob menu
3. Scroll the menu with your mouse and keyboard to ~1/3 from the bottom
4. Select "Bookmark" submenu

@bsclifton what do you think?

[bsclifton]

@luixxiul looks like great repro steps 👍