fix #10405 and #10303 partially: removes the scroll area for the style page

[3nids]

This remove the scroll area in the style page of the vector layer properties.
I think if scroll is needed it should be done in the corresponding subpages (such as point displacement, categorized, etc).

[dakcarto]

@3nids I don't think this is the appropriate fix, and should be reverted. The fix should be within the combobox widget itself, e.g. limit its width, self-adjusting if needed, etc.

Now the Vector properties dialog is way too wide, especially when viewing symbology. When switching to symbology, if the dialog is not wide enough, the icon sidebar is now forced to icon mode, and can not have its splitter moved until the dialog is made bigger. Also, resizing the dialog now forces resizing of the sidebar. The previous main scroll area kept this from happening.

Alternatively, a scroll area could be added to symbology, but that is not much different than reverting this, and does not address the sidebar resizing issue.

Also, you gave no time for anyone to test this before pushing it. The PR was up for only 7 hours!

[3nids]

@dakcarto hi, sorry for not letting up long enough. I reverted this and set up a maximum width of 500px for the widget in categorized and graduated.