Fix annotation rendering when OSD has viewport margin.

When users configure a viewport margin for OSD (via
`osdConfig.viewportMargins`), annotation rendering would be broken,
since the `osd.viewport.getBoundsNoRottate()` call to get the viewport
boundary would return the viewport *without* the margin, which would
lead to wrong calculations down the line.
The fix is to simply call `osd.viewport.getBoundsNoRotateWithMargins`
instead to obtain the correct full viewport size.