I tried:
The location is correct, the file is called CurrentSettings.vssettings
I modified the line:
<add_toolbar Menu="{000D7B18-CDE4-49F0-B194-FE3E25BBF096}:00000002"
Name="GitExtensions" MenuType="toolbar" />
by adding Visibility="hide" FullScreen="hide"
Result:
<add_toolbar Menu="{000D7B18-CDE4-49F0-B194-FE3E25BBF096}:00000002"
Name="GitExtensions" MenuType="toolbar"
Visibility="hide" FullScreen="hide"/>